Self-assembly and mineralization of full-length human amelogenin and its functional fragments / 华西口腔医学杂志

OBJECTIVES@#To investigate the dynamic process of the self-assembly behaviors of a full-length human amelogenin (AM) and its functional fragments tyrosine-rich amelogenin peptide (TRAP) and leucine-rich amelogenin peptide(LRAP) @*METHODS@#The full-length human AM and its functional fragments, TRAP and LRAP, were reassembled and purified @*RESULTS@#When pH=8, the full-length human AM and TRAP assembly started spontaneously and formed "nanospheres" after 15 min.The nanospheres formed by TRAP existed independently, with a uniform size but without obvious internal structures. The full-length AM was assembled hierarchically, which formed "nanospheres" and further extended in all directions, formed a chain structure, and then aggregated into a net. The self-assembly behavior of LRAP was not obvious. Proteins mostly existed in the form of monomers without "nanosphere" formation. Only few oligomers were observed. The full-length AM was induced independently for 3 days to form rod-shaped HA crystals. TRAP and LRAP proteins were added, after 3 days the crystal elongation was obvious in the c axis, but the growth in plane A and plane B was poor.@*CONCLUSIONS@#The self-assembly and mineralization behaviors of full-length human AM, TRAP, and LRAP were consistent with the directional growth mechanism of HA crystals

The C-terminus of the amelogenin peptide promotes the proliferation of alc ameloblasts through accelerating cell cycle / 中国组织工程研究

BACKGROUND: C-terminus of the amelogenin peptide (AMG-CP) is a small molecular endogenous peptide that is highly shown that AMG-CP can regulate the proliferation and differentiation of cementoblasts, bone marrow mesenchymal stem cells and periodontal ligament fibroblasts, but the biological function of AMG-CP on ameloblasts has not been elucidated. O conserved among species. It is involved in important physiological processes during tooth development. Some studies have BJECTIVE: To investigate the effects of different concentrations of AMG-CP on the proliferation of ALC ameloblasts and its underlying mechanisms. METHODS: AMG-CP was successfully synthesized and determinated by liquid chromatography and mass spectrometry. The effects of AMG-CP at 0, 0.5, 1, 2 mg/L on the proliferation of ALC ameloblasts were observed by xCELLigence RTCA cell analysis system in real time. The effect of AMG-CP at 0, 1, 2 mg/L on cell cycle of ALC was detected by flow cytometry. Real-time PCR was used to detect the expression of cyclin D1, CDK4, MCM2, MCM5 mRNA in ALC cells treated with AMG-CP at 0, 1, 2 mg/L. Western blot was carried out to evaluate the effect of AGM-CP at 0, 1 mg/L on MAPK-ERK1/2 pathway by detecting the expression of phosphorylated ERK1/2 and total ERK1/2 in ALC cells. Pathway blockade assay was performed by using ERK1/2 blocker U0126 to pretreat ALC cells. Then cell proliferation ability as well as phosphorylated ERK1/2 expression was analyzed by xCELLigence RTCA cell analysis system and western blot. RESULTS AND CONCLUSION: Compared with the control group, AMG-CP promoted the proliferation of ALC cells, and decreased the population doubling time in a dose-depending manner. Flow cytometry detected the acceleration of cell cycle after treatment with AMG-CP. The results of Real-time PCR showed that AMG-CP upregulated cell cycle-related genes (cyclin D1, CDK4, MCM2, MCM5) expression. Western blot results showed that AMG-CP could upregulate the expression of phosphorylated ERK1/2 and activate MAPK-ERK1/2 signaling pathway in ALC cells. After U0126 was used to inhibit the MAPK-ERK1/2 pathway, the ability of AMG-CP promoting ALC proliferation was inhibited. These results suggest that AMG-CP has a potential to activate MAPK-ERK1/2 pathway, accelerate the process of cell cycle, and then promote the proliferation of ALC cells, all of which indicate that AMG-CP has the potential to promote the proliferation of ameloblasts.

Research progress on the relationship between enamel-related gene polymorphisms and caries susceptibility / 口腔疾病防治

@#Caries is a frequently occurring oral disease that is caused by chronic, progressive destruction of dental hard tissue. The enamel is the superficial layer of the tooth crown; enamel formation-related genes play an important role in the development of enamel, and enamel demineralization is a prerequisite for the occurrence of caries. Therefore, this paper reviewed the relationship between enamel-related gene polymorphisms and caries susceptibility and its possible mechanisms to provide new ideas for the prevention and treatment of caries. The results of a literature review showed that the gene polymorphisms related to enamel formation may increase or decrease susceptibility to caries by influencing the development and structure of enamel. For example, ENAM rs3796703 CT can increase the susceptibility to caries, and AMBN rs34538475 TT can reduce the susceptibility to caries. In the future, the detection and analysis of polymorphisms related to enamel formation that affect the structure or development of enamel may serve as a clinical method to evaluate the susceptibility of caries, which is of great significance for the early prevention and treatment of the disease.

Paciente masculino con cariotipo 46 XX negativo para el gen SRY y sin ambigüedad genital: reporte de un caso / Male patient 46, XX SRY -negative and unambiguous genitalia: A case report

En la mayoría de los casos, la diferenciación sexual masculina ocurre con la participación del gen SRY. Sin embargo, se pueden presentar otros genotipos excepcionales, como en el caso que se presenta en este reporte. Se trata de un paciente adulto de sexo masculino atendido en el Servicio de Paternidades del Instituto de Genética de la Universidad Nacional de Colombia. Se le hicieron los análisis del gen de la amelogenina y de repeticiones cortas en tándem (Short Tandem Repeat, STR) específicas para el gen SRY con estuches comerciales de identificación humana, así como los de cariotipo convencional e hibridación in situ fluorescente del SRY, y el estudio de microdeleciones del cromosoma Y mediante reacción en cadena de la polimerasa (PCR). Se le hizo la evaluación clínica y se le brindó asesoramiento genético. El paciente no presentaba ambigüedad genital, su cariotipo era 46 XX, y el perfil molecular era negativo para el gen SRY y positivo para el ZFY. Se le diagnosticó un trastorno de diferenciación sexual 46 XX testicular no sindrómico, una rara condición genética. Solo el 20 % de los pacientes con este diagnóstico son negativos para SRY y exhiben perfiles moleculares diversos. La información disponible parece indicar que el ZFY está relacionado con la diferenciación sexual masculina, aún en ausencia del gen SRY.

In most cases, male sexual differentiation occurs with SRY gene mediation. However, exceptional genotypes have been identified, as shown in this paper. This was a male adult patient seen at the Servicio de Paternidades, Instituto de Genética, Universidad Nacional de Colombia. The following procedures were carried out: Amelogenin gene and short tandem repeat analyses using human identification commercial kits, conventional karyotype, SRY fluorescent in situ hybridization, PCR analysis for Y chromosome microdeletions, clinical evaluation, and genetic counseling. We present an adult male with unambiguous genitalia, karyotype 46,XX, and an SRY negative and ZFY positive molecular profile. The diagnosis of nonsyndromic 46,XX testicular disorder of sex development (DSD) -a rare genetic condition- was established. Only 20 % of similarly diagnosed patients are SRY negative and exhibit diverse molecular profiles. Until now, available evidence seems to indicate that, even in the absence of SRY, the ZFY factor is involved in male sexual differentiation.

Immunohistochemical study of amelogenin binding proteins in an amelogenin point mutation mouse / Estudio inmunohistoquímico de proteínas de unión de la amelogenina en un ratón con mutación puntual de amelogenina

Amelogenin is one of the enamel matrices secreted by ameloblasts. A mutation of the amelogenin gene can cause hereditary dental enamel defects known as amelogenesis imperfecta (AI). Since lysosome-associated membrane protein-1 (LAMP-1), -3 (LAMP-3), and 78kDa glucose-related protein (Grp78) were identified as binding proteins of amelogenin, several studies have suggested the involvement of these binding proteins with the cell kinetics of ameloblasts in normal or abnormal conditions. The purpose of this study is to investigate the distribution of these amelogenin binding proteins in the ameloblast cell differentiation of mice with a point mutation of the amelogenin gene (Amelx*). The incisors of Amelx* mice had a white opaque color and the tooth surface was observed to be rough under a scanning electron microscope. Among the sequential ameloblast cell differentiation in the Amelx* mice, the shape of ameloblasts at the transition stage was irregular in comparison to those in wild-type (WT) mice. Immunostaining of Grp78 revealed that the whole cytoplasm of the transition stage ameloblasts was immunopositive for Grp78 antibody, while only the distal part of cell was positive in the WT mice. Furthermore, in the Amelx* mice, the cytoplasm of the transition stage ameloblasts was immunopositive for LAMP-1 and LAMP-3. These results suggest that Amelx* may cause the abnormal distribution of amelogenin binding proteins in the cytoplasm of ameloblasts.

La amelogenina es una de las matrices de esmalte secretadas por los ameloblastos. Una mutación del gen de amelogenina puede causar defectos hereditarios del esmalte dental conocidos como amelogénesis imperfecta (AI). Dado que la proteína de membrana asociada a lisosoma-1 (LAMP-1), -3 (LAMP-3) y la proteína relacionada con la glucosa de 78 kDa (Grp78) se identificaron como proteína de unión a amelogenina, varios estudios han sugerido la participación de estas proteínas con la cinética celular de los ameloblastos en condiciones normales o anormales. El objetivo del estudio fue investigar la distribución de LAMP-1, LAM-3 y Grp78 durante la diferenciación celular de ameloblastos de ratones con una mutación puntual del gen de amelogenina (Amelx*). Los incisivos de los ratones Amelx* presentaron un color blanco opaco y se observó en microscopio electrónico de barrido que la superficie del diente era áspera. La diferenciación celular secuencial y la forma de los ameloblastos en la etapa de transición en los ratones Amelx* fue irregular en comparación con los ratones silvestres (RS). La inmunotinción de Grp78 reveló que todo el citoplasma de los ameloblastos en etapa de transición fue inmunopositivo para el anticuerpo Grp78, mientras que solo la parte distal de la célula fue positiva en los ratones RS. Además, en ratones Amelx*, el citoplasma de los ameloblastos en etapa de transición fue inmunopositivo para LAMP-1 y LAMP-3. Estos resultados sugieren que Amelx* puede causar distribución anormal de proteínas de unión a amelogenina en el citoplasma de los ameloblastos.

Alteración del gen AMELX en amelogénesis imperfecta. Una breve revisión / Alteration of the AMELX gene in amelogenesis imperfecta. A brief review

Resumen La amelogénesis imperfecta es un grupo de trastornos de desarrollo del esmalte dental asociados principalmente con mutaciones en el gen AMELX. Clínicamente presenta diferentes fenotipos que afectan la estructura y función del esmalte, tanto de la dentición primaria como secundaria. El objetivo de este estudio fue realizar una revisión bibliográfica de las funciones y mutaciones de AMELX relacionadas con amelogénesis imperfecta. Se llevó a cabo una revisión bibliográfica en dos bases de datos: PubMed y Web of Science, usando las palabras clave “AMELX”, “amelogenina”, “amelogénesis imperfecta” y “mutación de AMELX”. Fueron revisados 40 artículos y se encontró que AMELX es el gen predominante en el desarrollo del esmalte dental y de la amelogénesis imperfecta, alterando la estructura de la amelogenina. En los últimos años se han descrito las características en el proceso de amelogénesis imperfecta con diferentes fenotipos de esmalte hipoplásico o hipomineralizado y se han reportado diferentes mutaciones, con lo que se ha determinado la secuenciación del gen y las posiciones de las mutaciones.

Abstract Amelogenesis imperfecta is a group of developmental disorders of the dental enamel that is mainly associated with mutations in the AMELX gene. Clinically, it presents different phenotypes that affect the structure and function of dental enamel both in primary and secondary dentition. The purpose of this study was to conduct a literature review on the AMELX functions and mutations that are related to amelogenesis imperfecta. A literature search was carried out in two databases: PubMed and Web of Science, using the keywords “AMELX”, “amelogenin”, “amelogenesis imperfecta” and “AMELX mutation”. Forty articles were reviewed, with AMELX being found to be the predominant gene in the development of dental enamel and amelogenesis imperfecta by altering the structure of amelogenin. In the past few years, the characteristics of the amelogenesis imperfecta process have been described with different phenotypes of hypoplastic or hypo-mineralized enamel, and different mutations have been reported, by means of which the gene sequencing and the position of mutations have been determined.

Regeneration of Neural Networks in Immature Teeth with Non-Vital Pulp Following a Novel Regenerative Procedure

BACKGROUND AND OBJECTIVES: Recombinant amelogenin protein (RAP) was reported to induce soft-tissue regeneration in canine infected endodontically treated permanent teeth with open apices. To characterize identities of the cells found in the RAP regenerated tissues compared to authentic pulp by identifying: 1) stem cells by their expression of Sox2; 2) nerve fibers by distribution of the axonal marker peripherin; 3) axons by their expression of calcitonin gene–related peptide (CGRP); 4) the presence of astrocytes expressing glial fibrillary acidic proteins (GFAP).METHODS: A total of 240 open-apex root canals in dogs were used. After establishment of oral contamination to the pulp, the canals were cleaned, irrigated, and 120 canals filled with RAP, and the other 120 with calcium hydroxide.RESULTS: After 1, 3, and 6 months, teeth were recovered for immune-detection of protein markers associated with native pulp tissues. Regenerated pulp and apical papilla of RAP group revealed an abundance of stem cells showing intense immunoreactivity to Sox2 antibody, immunoreactivity of peripherin mainly in the A-fibers of the odontoblast layer and immunoreactivity to CGRP fibers in the central pulp region indicative of C-fibres. GFAP immunoreactivity was observed near the odontoblastic, cell-rich regions and throughout the regenerated pulp.CONCLUSIONS: RAP induces pulp regeneration following regenerative endodontic procedures with cells identity by gene expression demonstrating a distribution pattern similar to the authentic pulp innervation. A- and C-fibers, as well as GFAP specific to astrocytic differentiation, are recognized. The origin of the regenerated neural networks may be derived from the Sox2 identified stem cells within the apical papilla.

Effect of recombinant human amelogenin-loaded PCLA-PEG-PCLA hydrogels on biological properties of human periodontal ligament fibroblasts / 上海交通大学学报（医学版）

Objective • To determine the effect of recombinant human amelogenin (rhAm)-loaded PCLA-PEG-PCLA hydrogels on cell proliferation, immigration, attachment and osteogenic differentiation of human periodontal ligament fibroblasts (HPDLFs). Methods • HPDLFs were obtained by tissue block method in vitro from extracted premolars and the 3rd-5th passages of HPDLFs were treated with DMEM medium (control group), 20 μg/mL rhAm (rhAm group) or rhAm-loaded PCLA-PEG-PCLA hydrogels (rhAm-loaded hydrogel group). Proliferation activity was measured by CCK-8, while cell migration was assayed both by wound-healing experiment in vitro and Transwell experiment. Cell attachment was measured by hemocytometer and observed by scanning electron microscope. Osteogenic differentiation was measured by real-time PCR, with ALP, Runx2, CEMP1 and CAP as the target genes. Results • RhAm-loaded PCLA-PEG-PCLA hydrogels had no significant effect on cell growth curve of HPDLFs, but promoted cell proliferation after 3 days (P<0.05). RhAm accelerated cell migration mostly both in wound-healing experiment and Transwell experiment, with rhAm-loaded hydrogels in the second place. RhAm-loaded hydrogels promoted cell attachment, and in the 4th hour the promotion was of statistic significance (P<0.05). Meanwhile cells of rhAm group and rhAm-loaded hydrogel group had a better stretch condition than control group under the scanning electron microscope. After culture with rhAm-loaded hydrogels, ALP, Runx2, CEMP1, and CAP mRNA were upregulated in different time points. Conclusion • Recombinant human amelogenin-loaded PCLA-PEG-PCLA hydrogels can significantly improve proliferation, attachment and osteogenic differentiation of HPDLFs, but has no effect on cell migration on a statistical scale.

Identification of Amelogenin Gene on Burnt Teeth Samples through Nested Polymerase Chain Reaction Amplification for Sex Identification / Jurnal Sains Kesihatan Malaysia

@#Sex determination is one of the basic components in victim identification. This study aims to ascertain the sex of an individual from burnt teeth samples exposed at different temperature and time through nested polymerase chain reaction (PCR) on the amelogenin (AMEL) sex marker, to calculate the specificity and sensitivity, and to compare with previous relevant studies. A total of 17 teeth samples was subjected to burning at different temperatures ranging from 100°C to 500°C, at 2 to 10 minutes. The whole tooth was used for deoxyribonucleic acid (DNA) extraction by phenol-chloroform method. All samples were quantified for DNA concentration and then analyzed with nested PCR using two pairs of AMEL primer and results of sex typing were recorded. Out of 17 samples, genomic DNA extracted from 6 samples have concentrations ranging from 27.3 – 130.6 ng/µL. Nested PCR could amplify 16 samples for AMEL gene. Sex typing using AMEL gene showed 76.47% accuracy. Sensitivity of AMEL primer was increased from 6.67% to 63.64% using nested PCR technique; specificity of both external and internal primer was reported at 100%. Nested PCR of AMEL gene proved to be a suitable method for unequivocal determination of sex from degraded DNA samples.

Sex determination by amplification of amelogenin gene from dental pulp tissue by polymerase Chain Reaction

Forensic odontology necessarily involves the application of dentistry along with various other branches of sciences which deals with proper handling, examination, evaluation, and presentation of dental evidences, that aids to investigate a crime and deliver justice. Sex determination is a part of forensic odontology and an essential priority when traditional identification of the deceased becomes impossible. Aim: To determine Sex by analysis of the Amelogenin gene using Polymerase Chain Reaction (PCR) method on Deoxyribose nucleic acid (DNA) isolated from dental pulp, which was exposed to various environmental conditions created artificially to mimic a forensic scenario. Materials and Method: This in-vitro study was conducted by subjecting extracted teeth to various conditions imitating a forensic scene, viz. desiccation at room temperatures, immersion in salt water, burial in soil and even exposing to extremes of temperatures. DNA was extracted from dental pulp tissue and sex determination was achieved by amplification of the amelogenin gene through AMEL gene based primers in PCR. Result: Among all the samples used in this study, DNA could be extracted from all, except from those that were subjected to a temperature of 350 °C. DNA amplification and sex determination of the samples were found to be accurate when compared to sex of the individual which was recorded initially, during collection of teeth samples. Conclusion: This study shows teeth to be a potent source of DNA even in extreme environmental conditions, barring high temperatures and determination of sex by PCR amplification of AMEL markers to be quite reliable.

Detection and Analysis of 12 Suspected Amelogenin Allelic Loss Cases / 法医学杂志

OBJECTIVES@#To observe and analyse the Amelogenin allelic loss in parent-child identification cases, and to explore the type and mechanism of Amelogenin allelic loss as well as its influence on gender identification and solutions.@*METHODS@#After the detection by SiFaSTR™ 23plex DNA identification system, samples had the characteristics of the peak area of Amelogenin X was the same as the one of adjacent heterozygote or lower than one half of adjacent homozygote in females while Amelogenin X loss was observed in males were selected. X chromosome STR （X-STR） typing and Amelogenin X sequencing were performed. The samples with Amelogenin Y loss in males were confirmed by the detection of Y chromosome STR typing and sex-determining region of Y （SRY）. The type and rate of Amelogenin allelic loss were confirmed and calculated, and the mechanism and influence of this variation were also analysed.@*RESULTS@#Amelogenin X allelic loss was observed in one male sample, the mutation in primer-binding region was confirmed by sequencing. The suspected Amelogenin X allelic loss was observed in four female samples, but the mutation in primer-binding region was confirmed by sequencing in only one sample. Amelogenin Y allelic loss was observed in seven male samples, SRY positive cases was detected in five of them, and two were SRY negative. Y-STR type was detected in four cases of the five SRY positive cases, which was not detected in the two SRY negative cases. The rate of Amelogenin allelic loss was about 0.029%.@*CONCLUSIONS@#Amelogenin X allelic loss does not affect the gender identification, but Amelogenin Y allelic loss may cause wrong gender identification. Thus, Y-STR or SRY should be detected for gender confirmation. When Y-STR genotypes are not detected in a "male" whose SRY detection is also negative, then the chromosome karyotype analysis and sex differentiation related genes test should be taken to further confirm the gender.

Diversidad del ADN mitocondrial en restos óseos prehispánicos / Mitochondrial DNA diversity in prehispanic bone remains on the eastern Colombian Andes

Resumen Introducción. El ADN antiguo que se extrae de los restos óseos humanos permite analizar la composición genética de las poblaciones precolombinas y determinar las dinámicas poblacionales que dieron origen a la diversidad de las poblaciones contemporáneas. Objetivo. Determinar la diversidad genética y la relación con otras comunidades contemporáneas y antiguas de América, de los restos óseos asociados al Templo del Sol en Sogamoso, Colombia. Materiales y métodos. Se analizaron 13 individuos pertenecientes al periodo precolombino muisca (siglos IX-XVI d. C.), provenientes de los alrededores del Templo del Sol en Sogamoso, Boyacá, Andes orientales colombianos. Se amplificó el ADN mitocondrial (ADNmt) y se determinaron los polimorfismos de la longitud de los fragmentos de restricción (Restriction Fragment Length Polymorphism, RFLP) para los cuatro haplogrupos amerindios (A, B, C y D). Además, se amplificaron y analizaron los marcadores autosómicos, incluida la amelogenina, y los marcadores de los polimorfismos de repeticiones cortas en tándem (Short Tandem Repeat, STR) del cromosoma Y. Resultados. El haplogrupo A fue el linaje mitocondrial más frecuente en esta población, seguido de los haplogrupos B y C; no se detectó el haplogrupo D. Los análisis de variación genética indicaron una diversidad semejante a la de las poblaciones pertenecientes a la familia lingüística chibcha, contemporánea en Colombia y Centroamérica. Se logró hacer la determinación molecular del sexo de los individuos estudiados y compararla con los datos osteológicos. Con una sola excepción, los datos bioantropológicos y moleculares concordaron. Conclusiones. Estos resultados aportan nuevos elementos a la hipótesis del origen centroamericano de los grupos chibchas del altiplano cundiboyacense con base en marcadores genéticos, y permitieron establecer el sexo y las relaciones de parentesco.

Abstract Introduction: DNA extracted from ancient human bones allows to analyze the genetic makeup of preColumbian populations and to determine the dynamics that gave rise to the diversity of contemporary populations. Objective: To determine the genetic diversity of skeletal remains associated with the Templo del Sol (Sun Temple) and their relationship with other contemporary and ancient communities of America. Materials and methods: We analyzed 13 individuals belonging to the pre-Columbian Muisca Period (IX-XVI centuries AD) from the vicinities of the Templo del Sol (Sun Temple) (Sogamoso, Boyacá) in the eastern Colombian Andes. Mitochondrial DNA was amplified and RFLPs were performed in order to type the four traditional Amerindian haplogroups (A, B, C and D). In addition, autosomal markers including amelogenin and Y-chromosome STRs were amplified. Results: Among the observed mitochondrial lineages, haplogroup A was the most frequent, followed by haplogroups B and C; no evidence of haplogroup D was found. The genetic variation analysis indicated a similar diversity of pre-Columbian Muiscas to that of contemporary populations belonging to the Chibcha linguistic family from Colombia and Central America. Molecular sexing was accomplished and it was compared to osteological data. With only one exception, anthropological and molecular data were consistent. Conclusions: Our results contribute new genetic elements supporting the hypothesis of Central American origin of the Chibcha groups of the Cundiboyacense plateau, and allowed sex typing and kinship evaluations.

Expression of enamel proteins in rough endoplasmic reticulum and golgi complex in human dental germs / Expresión de proteínas del esmalte en retículo endoplásmico rugoso y complexo golgiensis en gérmenes dentales humanos

Tooth enamel is the hardest tissue in the body. The organic matrix configuration is provided by the main proteins amelogenin, ameloblastin and enamelysin (MMP20), an enzyme that helps to shape the matrix. The aim of this study was to determine by histochemistry the expression of amelogenin and enamelysin through the rough endoplasmic reticulum in the late stages of amelogenesis, and its expression in the Complexus golgiensis (Golgi complex / Golgi apparatus) in the early stages in human fetuses. In early stages a colocalization of both proteins inside the Golgi apparatus was found, being more evident the relationship between Golgi and amelogenin (99.92 %). In the late stage, a colocalization of both proteins and rugged endoplasmic reticulum was found. With enamelysin being more evident in relation with rough endoplasmic reticulum (99.95 %). Our findings demonstrated the presence of amelogenin and enamelysin in odontoblast and ameloblast. However, the presence of these two proteins in odontoblast remains unknown.

El esmalte dental es el tejido más duro del cuerpo. La configuración de la matriz orgánica es proporcionada por las proteínas principales amelogenina, ameloblastina y enamelisina (MMP20), una enzima que ayuda a dar forma a la matriz. El objetivo de este estudio fue determinar mediante histoquímica la expresión de amelogenina y enamelisina a través del retículo endoplasmático rugoso en las últimas etapas de la amelogénesis , y su expresión en el Complexo golgiensis en las primeras etapas de formación en fetos humanos. En las primeras etapas se observó colocalización de ambas proteínas en el interior del Complexo golgiensis, siendo más evidente la relación entre Golgi y amelogenina (99,92 %). En la última etapa, se identificó una colocalización de ambas proteínas y retículo endoplásmico rugoso. Resulto más evidente la enamelisina en relación con el retículo endoplasmático rugoso (99,95 %). Nuestros resultados demostraron la presencia de amelogenina y enamelisina en odontoblastos y ameloblastos, sin embargo se desconoce la presencia de estas dos proteínas en odontoblastos.

Pathogenesis of dental fluorosis: biochemical and cellular mechanisms / Patogénesis de la fluorosis dental: mecanismos bioquímicos y celulares

Abstract. The mechanisms involved in the development of dental fluorosis are still unknown. The development of in vivo and in vitro models using biologically relevant concentrations of fluoride for the emergence of fluorosis has allowed suggesting hypotheses that contribute to the understanding of the mechanisms that produce this defect in enamel development, with high prevalence in Colombia. This topic review presents an update on the normal mechanisms of the formation of enamel and how they are affected by exposure to high concentrations of fluoride. This is a thorough review of the deleterious effects of fluoride on the cells and the extracellular matrix, especially during the maturation stage, resulting in a delay of the removal of the protein matrix of amelogenins, as well as the appearance of mottled enamel-a characteristic of dental fluorosis. Finally, it shows the perspectives of the study of this defect in enamel development from biochemistry and cellular and molecular biology.

RESUMEN. Los mecanismos involucrados en el desarrollo de la fluorosis dental aún no se conocen a cabalidad. El desarrollo de modelos in vivo e in vitro que utilizan concentraciones de fluoruro biológicamente relevantes para la aparición de fluorosis ha permitido el planteamiento de hipótesis que aportan cada vez más al conocimiento de los mecanismos que generan este defecto del desarrollo del esmalte, de alta prevalencia en Colombia. Esta revisión presenta una actualización sobre los mecanismos normales de la formación del esmalte y cómo estos se ven afectados por la exposición a altas concentraciones de fluoruro. Se presenta una revisión en detalle de los efectos deletéreos del fluoruro sobre las células y sobre la matriz extracelular, especialmente durante la etapa de maduración, que tendrán como consecuencia el retraso de la remoción de la matriz proteica de amelogeninas y se traducirá en la apariencia de esmalte moteado, característica de la fluorosis dental. Por último, se muestran las perspectivas del estudio de este defecto del desarrollo del esmalte desde la bioquímica y la biología celular y molecular.

The analysis of allelic deletion in 4 cases of Amelogenin loci in paternity testing / 复旦学报（医学版）

Objective To apply PowerPlex(R) 21 System Kit and AGCU 21 + 1 STR Fluorescence Detection Kit as supplementary detection kit in some samples with Amelogenin locus X deletion.Methods While with the help of Investigator Argus X-12 Kit,MicroreaderTM 19X ID System kit and the application of capillary electrophoresis,the complete X pattern of these four samples can be identified.Results From Mar,2013 to Dec,2016,4 cases of male samples with Amelogenin locus X deletion have been found.Conclusions Sometimes Amelogenin locus X deletion may happen when using PowerPlex(R)21 System Kit and AGCU 21 + 1 STR Fluorescence Detection Kit,while validating with other forensic biology detection kit can assure the accuracy of genotyping.

Study of human leucine-rich amelogenin peptide and its regulation of mineralization by cryogenic transmission electron microscopy / 华西口腔医学杂志

<p><b>OBJECTIVE</b>Recombinant human leucine-rich amelogenin peptide (LRAP) was studied by cryogenic transmission electron microscopy (TEM); evaluation focused on its self-assembly and crystal growth in vitro.</p><p><b>METHODS</b>Human LRAP was recombined through prokaryotic expression vector pCold-SUMO and transformed into Escherichia coli BL21plys to acquire purified proteins. Cryogen TEM recorded assembly and self-assembling of LRAP from pH 3.5 to pH 8.0, and the hydroxyapatite crystal growth in the mixture of LRAP protein solution and artificial saliva was observed using TEM and selected area electron diffraction.</p><p><b>RESULTS</b>More than 90% purity LRAP was expressed, purified and identified as described in methods. LRAP linked into oligomers, nanospheres, nanochains, and microribbons, whereas pH value increased from 3.5 to 8.0. Mature hydroxyapatite crystal growth was guided in artificial saliva filled with calcium phosphate.</p><p><b>CONCLUSIONS</b>LRAP is simplified amelogenin functional domain and conserved the basic characters of amelogenin such as self-assembling and inducing crystallization along c axis. In the area of acellular synthesis of hydroxyapatite using extracellular enamel matrix protein, LRAP is one of candidate repair materials for irregular hard tissue defection.
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Research Progress on Gene Alterations of Amelogenin Locus in Gender Identification / 法医学杂志

There are two kinds of amelogenin gene mutation, including mutation in primer-binding region of amelogenin gene and micro deletion of Y chromosome encompassing amelogenin gene, and the latter is more common. The mechanisms of mutation in primer-binding region of amelogenin gene is nucleotide point mutation and the mechanism of micro deletion of Y chromosome encompassing amelogenin gene maybe non-allelic homologous recombination or non-homologous end-joining. Among the population worldwide, there is a notably higher frequency of amelogenin gene mutations in Indian population, Sri Lanka population and Nepalese population which reside within the Indian subcontinent. Though amelogenin gene mutations have little impact on fertility and phenotype, they might cause incorrect result in gender identification. Using composite-amplification kit which including autosomal STR locus, amelogenin gene locus and multiple Y-STR locus, could avoid wrong gender identification caused by amelogenin gene mutation.

Recognition of Y Fragment Deletion by Genotyping Graphs after Amplified by PowerPlex® 21 Detection Kit / 法医学杂志

OBJECTIVES@#To recognize the possibility of Y fragment deletion of Amelogenin gene intuitively and simply according to the genotyping graphs.@*METHODS@#By calculating the ratio of total peak height of genotyping graphs, the statistics of equilibrium distribution between Amelogenin and D3S1358 loci, Amelogenin X-gene and Amelogenin Y-gene, and different alleles of D3S1358 loci from 1 968 individuals was analyzed after amplified by PowerPlex® 21 detection kit.@*RESULTS@#Sum of peak height of Amelogenin X allele was not less than 60% that of D3S1358 loci alleles in 90.8% female samples, and sum of peak height of Amelogenin X allele was not higher than 70% that of D3S1358 loci alleles in 94.9% male samples.@*CONCLUSIONS@#The result of genotyping after amplified by PowerPlex® 21 detection kit shows that the possibility of Y fragment deletion should be considered when only Amelogenin X-gene of Amelogenin is detected and the peak height of Amelogenin X-gene is not higher than 70% of the total peak height of D3S1358 loci.

Research Progress on Gene Alterations of Amelogenin Locus in Gender Identification / 法医学杂志

There are two kinds ofamelogeningene mutation, including mutation in primer-binding re-gion ofamelogeningene and micro deletion of Y chromosome encompassingamelogeningene, and the latter is more common. The mechanisms of mutation in primer-binding region ofamelogeningene is nu-cleotide point mutation and the mechanism of micro deletion of Y chromosome encompassingamelo-geningene maybe non-allelic homologous recombination or non-homologous end-joining. Among the population worldwide, there is a notably higher frequency ofamelogeningene mutations in Indian popu-lation, Sri Lanka population and Nepalese population which reside within the Indian subcontinent. Thoughamelogeningene mutations have little impact on fertility and phenotype, they might cause incor-rect result in gender identification. Using composite-amplification kit which including autosomal STR lo-cus,amelogeningene locus and multiple Y-STR locus, could avoid wrong gender identification caused byamelogeningene mutation.

Recognition of Y Fragment Deletion by Genotyping Graphs after Amplified by PowerPlex?21 Detection Kit / 法医学杂志

Objective To recognize the possibility of Y fragment deletion of Amelogenin gene intuitively and simply according to the genotyping graphs.Methods By calculating the ratio of total peak height of genotyping graphs, the statistics of equilibrium distribution between Amelogenin and D3S1358loci,Amelo-genin X-gene and Amelogenin Y-gene, and different alleles of D3S1358loci from 1968 individuals was analyzed after amplified by PowerPlex? 21 detection kit.Results Sum of peak height of Amelogenin X allele was not less than 60% that of D3S1358loci alleles in 90.8% female samples, and sum of peak height of Amelogenin X allele was not higher than 70% that of D3S1358loci alleles in 94.9% male samples.Conclusion The result of genotyping after amplified by PowerPlex? 21 detection kit shows that the possibility of Y fragment deletion should be considered when only Amelogenin X-gene of Amelo-geninis detected and the peak height of AmelogeninX-gene is not higher than 70% of the total peak height of D3S1358loci.