RESUMEN
Balanced reciprocal and Robertsonian translocations are the most common structural chromosome abnormalities in humans, with incidences of 0.7 and 1.23 per 1000. These translocations can affect fertility and/or pregnancy outcome because of possibly impaired production of gametes with an unbalanced zygote caused by the parental arrangement. Fertility problems in male translocation carriers are because of various degrees of sperm alterations that are directly related to the disturbance of the meiotic process. Investigation of human sperm chromosomes was performed by karyotyping spermatozoa after penetration of zona-free hamster oocytes, karyotype analysis now being possible to analyse the segregation patterns by using fluorescent in situ hybridization (FISH). Here, we document the results of meiotic segregation analysis for four Robertsonian and four reciprocal translocation carriers by FISH. In the sperm of Robertsonian translocation males, the majority of spermatozoa were normal/balanced. On the other hand, males with reciprocal translocations demonstrated a high rate of unbalanced spermatozoa of about 50% on meiotic segregation, with an unusually high rate (23.5%) of 3 : 1 segregation. This knowledge can be used for genetic counselling of families with these types of translocations.
Asunto(s)
Segregación Cromosómica , Heterocigoto , Hibridación Fluorescente in Situ , Meiosis/fisiología , Espermatozoides/citología , Translocación Genética , Adulto , Animales , Cricetinae , Femenino , Humanos , Cariotipificación , Masculino , Interacciones Espermatozoide-ÓvuloRESUMEN
Inherited mutation of hypoxanthine guanine phosphoribosyltransferase, (HPRT) gives rise to Lesch-Nyhan syndrome or HPRT-related gout. We have identified 34 mutations in 28 Japanese, 7 Korean, and 1 Indian families with the patients manifesting different clinical phenotypes, including two rare cases in female subjects, by the analysis of all nine exons of HPRT from the genomic DNA and reverse transcribed mRNA using PCR technique coupled with direct sequencing.
Asunto(s)
Hipoxantina Fosforribosiltransferasa/deficiencia , Hipoxantina Fosforribosiltransferasa/genética , Mutación , Exones , Salud de la Familia , Femenino , Humanos , India , Japón , Corea (Geográfico) , Síndrome de Lesch-Nyhan/genética , Masculino , Fenotipo , Reacción en Cadena de la Polimerasa , ARN Mensajero/metabolismo , Análisis de Secuencia de ADN , SíndromeRESUMEN
Chinese hamster stocks with various structurally abnormal chromosomes have been produced by X irradiation. Among these stocks, 18 with various reciprocal translocations were used to investigate the participation of unbalanced gametes in fertilization and the development of unbalanced embryos. Among males as well as females heterozygous for the same translocation, there is no difference in the frequency of each disjunctional class. The participation of chromosomally unbalanced gametes in fertilization was investigated by chromosomal analysis of meiotic cells in heterozygotes for the 18 reciprocal translocations and pronuclei of fertilized ova obtained from crossing these heterozygotes. Compared with the expected frequencies from MII scoring, the frequencies of male pronuclei having a common deficiency of chromosome 1 (1q17-->1q42) or chromosome 3 (3p23-->3q31) decreased significantly in one-cell embryos. However, the frequencies of male pronuclei with other abnormalities were all consistent with those expected from MII scoring. In contrast, the frequencies of female pronuclei with any karyotype including the same abnormalities as those decreased in male pronuclei from the translocation heterozygotes were all consistent with those estimated from MII scoring. These results revealed clearly that most gametes with nullisomies as well as disomies for any chromosomal segments may participate in fertilization, whereas only male gametes nullisomic for certain segments of chromosomes 1 and 3 failed to participate in fertilization. The zygotic selection of chromosomal imbalance was also investigated by direct chromosomal and morphological analyses of preimplantation embryos from crosses between karyotypically normal females and male heterozygotes from the 18 stocks with various reciprocal translocations. These analyses revealed that some embryos were arrested in development at the two-cell stage. The karyotype of these two-cell embryos had a common deficiency in a segment of chromosome 1 or chromosome 2. Embryos with partial monosomy including chromosomes 1, 3, 4 and 5 showed arrested development at four- to eight-cell stages. Among day 4 embryos, some chromosomally unbalanced embryos, mainly with a deficiency of segments of chromosomes 1p, 1q, 2q, 5q, 7q and 8, had fewer blastomeres than karyotypically normal and balanced embryos. The homology between Chinese hamster and mouse chromosomes relating to abnormal embryogenesis at early stages has been partially confirmed from reported maps of chromosomes. The Chinese hamster is useful for further cytogenetic studies during the stages of meiosis and early embryogenesis.
Asunto(s)
Aneuploidia , Blastocisto , Cricetulus/genética , Muerte Fetal/genética , Espermatozoides/ultraestructura , Translocación Genética , Animales , Blástula , Deleción Cromosómica , Cricetinae , Cricetulus/embriología , Cruzamientos Genéticos , Desarrollo Embrionario y Fetal/genética , Femenino , Fertilización , Dosificación de Gen , Heterocigoto , Cariotipificación , Masculino , Meiosis , Embarazo , CigotoRESUMEN
Identifier (ID) elements are members of a family of short interspersed nuclear elements (SINEs) in rodents. We investigated the genomic organization and chromosomal distribution of the ID elements in the rat, mouse and Chinese hamster. Southern blot hybridization analysis revealed that the ID elements are widespread in the rat genome, but concentrated in the mouse and Chinese hamster genomes, and that the copy of ID elements in the rat is about 5 times and 50 times that in the mouse and Chinese hamster, respectively. FISH analysis showed that the ID elements are predominantly distributed in the R-band regions of rat chromosomes. In mouse and Chinese hamster chromosomes, no specific distribution pattern of the ID elements was found. Furthermore, we found a distinct group of derivative ID elements in the rat, which contain partially repeated ID core domains, by PCR amplification using an ID core sequence. Such derivatives were not found in either the mouse or Chinese hamster. These findings suggest that explosive amplification of the ID elements in the rat has been accompanied by the occurrence of derivative ID elements and a predominant localization to the R-band regions. Similar associations found in the Alu family, one of the human SINEs, allow us to speculate that the rat ID elements and the human Alu family have analogous functions in chromosomal organization.
Asunto(s)
Cromosomas/genética , Elementos de Nucleótido Esparcido Corto/genética , Animales , Secuencia de Bases , Southern Blotting , Cricetinae , Cricetulus , Cartilla de ADN/química , Sondas de ADN , Genoma , Humanos , Hibridación Fluorescente in Situ , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Ratas , Ratas Sprague-Dawley , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido NucleicoRESUMEN
Mutations in ZFHX1B, encoding Smad-interacting protein 1 (SIP1), have been recently reported to cause a form of Hirschsprung disease (HSCR). Patients with ZFHX1B deficiency typically show mental retardation, delayed motor development, epilepsy, microcephaly, distinct facial features, and/or congenital heart disease, in addition to the cardinal form of HSCR. To investigate the breadth of clinical variation, we studied DNA samples from six patients with clinical profiles quite similar to those described elsewhere for ZFHX1B deficiency, except that they did not have HSCR. The results showed the previously reported R695X mutation to be present in three cases, with three novel mutations-a 2-bp insertion (760insCA resulting in 254fs262X), a single-base deletion (270delG resulting in 91fs107X), and a 2-bp deletion (2178delTT resulting in 727fs754X)-newly identified in the other three. All mutations occurred in one allele and were de novo events. These results demonstrate that ZFHX1B deficiency is an autosomal dominant complex developmental disorder and that individuals with functional null mutations present with mental retardation, delayed motor development, epilepsy, and a wide spectrum of clinically heterogeneous features suggestive of neurocristopathies at the cephalic, cardiac, and vagal levels.
Asunto(s)
Anomalías Múltiples/genética , Codón sin Sentido/genética , Mutación del Sistema de Lectura/genética , Proteínas de Homeodominio/genética , Proteínas Represoras/genética , Adolescente , Adulto , Niño , Preescolar , Análisis Mutacional de ADN , Epilepsia/genética , Cara/anomalías , Femenino , Cardiopatías/congénito , Humanos , Lactante , Discapacidad Intelectual/genética , Masculino , Microcefalia/genética , Polimorfismo de Longitud del Fragmento de Restricción , ARN Mensajero/análisis , ARN Mensajero/genética , Caja Homeótica 2 de Unión a E-Box con Dedos de ZincRESUMEN
Rett syndrome is an X-linked dominant neurodevelopmental disorder that affects females almost exclusively. The recent identification of mutations of the methyl-CpG-binding protein 2 gene (MECP2) in patients with RTT, encouraged us to analyze the gene in 37 Japanese patients divided into classical RTT (14 cases), variant RTT (13 cases), and mentally retarded patients with Rett-like features (10 cases). Mutations in MECP2 were identified from most of the patients with classical and variant RTT (25 of 27 cases). Six reported common mutations were detected in 17 cases, and rare single nucleotide substitutions were found in 3 patients. In addition, one insertion mutation (1189insA) and four deletion mutations including one double deletion mutant (451delG, 100del4, 1124del53 and 881del289 plus 1187del8) were newly identified. In the 10 mentally retarded patients with Rett-like features, however, no mutation was detected in the coding region of MECP2. The finding of MECP2 mutations in 92.5% of patients with RTT indicates that RTT fulfilling the diagnostic criteria are due to genetic alteration.
Asunto(s)
Proteínas Cromosómicas no Histona , Proteínas de Unión al ADN/genética , Proteínas Represoras , Síndrome de Rett/genética , Sustitución de Aminoácidos , ADN/química , ADN/genética , Análisis Mutacional de ADN , Femenino , Genotipo , Humanos , Japón , Masculino , Proteína 2 de Unión a Metil-CpG , Mutagénesis Insercional , Mutación , Fenotipo , Mutación Puntual , Síndrome de Rett/patología , Eliminación de SecuenciaRESUMEN
Chromosome 14q +, which represents a chromosomal rearrangement involving the immunoglobulin heavy chain gene (IgH) locus, is a genetic hallmark of human multiple myeloma (MM). Here, we report the identification of (14;20)(q32;q11) chromosomal translocations found in MM cells. Double color fluorescence in situ hybridization analyses pinpointed the breakpoints at the 20q11 locus in two MM cell lines within a length of at most 680 kb between the KIAA0823 and MAFB gene loci. Among the transcribed sequences in the vicinity of the breakpoints, an ectopic expression of the MAFB gene, which is located at 450 - 680 kb telomeric to one of the breakpoints and encodes a member of the MAF family basic region / leucine zipper transcription factor, was demonstrated to be associated with t(14;20). This finding, together with that of a previous study describing its transforming activity, suggests that the MAFB gene may be one of the targets deregulated by regulatory elements of the IgH gene as a result of t(14;20).
Asunto(s)
Proteínas Aviares , Cromosomas Humanos Par 14 , Cromosomas Humanos Par 20 , Proteínas de Unión al ADN , Mieloma Múltiple/genética , Mieloma Múltiple/metabolismo , Proteínas Oncogénicas/biosíntesis , Transactivadores/biosíntesis , Factores de Transcripción , Translocación Genética , Northern Blotting , Cromosomas Artificiales de Levadura , Elementos de Facilitación Genéticos , Genes de Inmunoglobulinas/genética , Marcadores Genéticos , Humanos , Hibridación Fluorescente in Situ , Cariotipificación , Factor de Transcripción MafB , Modelos Genéticos , Fenotipo , ARN Mensajero/metabolismo , Lugares Marcados de Secuencia , Células Tumorales CultivadasRESUMEN
By fluorescence in situ hybridization (FISH), we constructed a chromosome map of 324 site-specific clones and 119 painting clones, which were isolated from a cosmid library of Chinese hamster genomic DNA. The site-specific clones were distributed among all chromosomes except chromosome 10 and the Y chromosome. On the other hand, FISH signals of painting clones were mainly found in heterochromatic regions. First, the various combinations of clones painting centromeric regions suggest that the centromeric heterochromatin of Chinese hamster chromosomes is extremely diverse in its repetitive sequence composition. Second, the long arm of the X chromosome and the whole Y chromosome, both heterochromatic regions, were simultaneously painted by many clones. The pattern of co-localization indicated that a proximal segment of the long arm of the X chromosome matches the complete long arm of the Y chromosome, whereas a distal segment of the long arm of the X chromosome is comparable to the whole short arm of the Y chromosome. Thus, these findings suggest that the corresponding segments of the X and Y-chromosomes have common repeated DNA elements.
Asunto(s)
Cósmidos/genética , Cricetulus/genética , Genoma , Mapeo Físico de Cromosoma , Animales , Bandeo Cromosómico , Pintura Cromosómica , Clonación Molecular , Cricetinae , Biblioteca Genómica , Heterocromatina/genética , Masculino , Cromosomas Sexuales/genéticaRESUMEN
The house musk shrew, Suncus murinus, is polymorphic for five Robertsonian translocations (Rb8.17, 9.13, 10.12, 11.16, 14.15). Fluorescence in situ hybridisation with a biotin-labelled oligonucleotide, (TTAGGG)7, was performed to localise the telomeric DNA sequences at Rb chromosomes of heterozygous shrews. Hybridisation signals were observed at both ends of all chromosomes, but not at the pericentromeric areas of any of the Robertsonian metacentrics. Our results indicate a complete loss of the telomeric sequences at the fusion points of the Rb metacentrics in S. murinus.
Asunto(s)
Centrómero , Musarañas/genética , Translocación Genética , Animales , Fusión Artificial Génica , Femenino , Hibridación Fluorescente in Situ/métodos , Masculino , TelómeroRESUMEN
By fluorescence in situ hybridization (FISH) using mouse probes, we assigned homologues for cathepsin E (Ctse), protocadherin 10 (Pcdh10, alias OL-protocadherin, Ol-pc), protocadherin 13 (Pcdh13, alias protocadherin 2c, Pcdh2c), neuroglycan C (Cspg5) and myosin X (Myo10) genes to rat chromosomes (RNO) 13q13, 2q24-->q25, 18p12-->p11, 8q32.1 and 2q22.1-->q22.3, respectively. Similarly, homologues for mouse Ctse, Pcdh13, Cspg5 and Myo10 genes and homologues for rat Smad2 (Madh2) and Smad4 (Madh4) genes were assigned to Chinese hamster chromosomes (CGR) 5q28, 2q17, 4q26, 2p29-->p27, 2q112-->q113 and 2q112-->q113, respectively. The chromosome assignments of homologues of Ctse and Cspg5 reinforced well-known homologous relationships among mouse chromosome (MMU) 1, RNO 13 and CGR 5q, and among MMU 9, RNO 8 and CGR 4q, respectively. The chromosome locations of homologues for Madh2, Madh4 and Pcdh13 genes suggested that inversion events were involved in chromosomal rearrangements in the differentiation of MMU 18 and RNO 18, whereas most of MMU 18 is conserved as a continuous segment in CGR 2q. Furthermore, the mapping result of Myo10 and homologues suggested an orthologous segment of MMU 15, RNO 2 and CGR 2.
Asunto(s)
Genes/genética , Animales , Cadherinas/genética , Catepsina E/genética , Mapeo Cromosómico , Cricetinae , Proteínas de Unión al ADN/genética , Hibridación Fluorescente in Situ , Proteínas de la Membrana/genética , Ratones , Miosinas/genética , Proteoglicanos/genética , Ratas , Proteína Smad2 , Proteína Smad4 , Transactivadores/genéticaRESUMEN
The structure of the coding region of mouse myosin X cDNA was determined. The predicted protein sequence indicated an approximately 240 kDa molecular mass with 2062 amino acids. When aligned with the structure predicted for calf myosin X (GenBank Accession No. U55042), extremely highly conserved pleckstrin homology domains and a myosin tail homology 4 domain were apparent in the tail region, suggesting their importance for myosin X's function. Northern blot analysis revealed the existence of a myosin X mRNA, 8.7 kb in size, in various mouse tissues, while a similar size of human type myosin X mRNA was recognized mainly in the testis. In addition to the adult-type transcripts in mice, a smaller embryo-specific mRNA, 4.8 kb in size, was identified in early to late embryonic stages, suggesting the presence of a shorter myosin X isoform in mouse embryos. In situ hybridization experiments with mouse testis revealed that myosin X mRNA was restricted to Sertoli cells at stages VIII-X of the spermatogenesis cycle, suggesting that myosin X is implicated in the supporting cells during the spermatid morphogenesis.
Asunto(s)
Miosinas/biosíntesis , Miosinas/genética , Secuencia de Aminoácidos , Animales , Proteínas Sanguíneas/química , Northern Blotting , Cromosomas Humanos Par 5 , Biblioteca de Genes , Humanos , Hibridación in Situ , Hibridación Fluorescente in Situ , Masculino , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Miosinas/química , Fosfoproteínas/química , Estructura Terciaria de Proteína , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Homología de Secuencia de Aminoácido , Células de Sertoli/metabolismo , Transducción de Señal , Talina/química , Testículo/metabolismo , Distribución TisularRESUMEN
The amino-terminal enhancer of split (AES) encodes a 197-amino acid protein that is homologous to the NH(2)-terminal domain of the Drosophila Groucho protein but lacks COOH-terminal WD40 repeats. Although the Drosophila Groucho protein and its mammalian homologs, transducin-like enhancer of split proteins, are known to act as non-DNA binding corepressors, the role of the AES protein remains unclarified. Using the yeast two-hybrid system, we have identified the protein-protein interaction between AES and the p65 (RelA) subunit of the transcription factor nuclear factor kappaB (NF-kappaB), which activates various target genes involved in inflammation, apoptosis, and embryonic development. The interaction between AES and p65 was confirmed by in vitro glutathione S-transferase pull down assay and by in vivo co-immunoprecipitation study. In transient transfection assays, AES repressed p65-driven gene expression. AES also inhibited NF-kappaB-dependent gene expression induced by tumor necrosis factor alpha, interleukin-1beta, and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 1, which is an upstream kinase for NF-kappaB activation. These data indicate that AES acts as a corepressor for NF-kappaB and suggest that AES may play a pivotal role in the regulation of NF-kappaB target genes.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas del Helminto/genética , Quinasa 1 de Quinasa de Quinasa MAP , FN-kappa B/antagonistas & inhibidores , Proteínas/metabolismo , Proteínas Represoras/metabolismo , Transcripción Genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Proteínas Co-Represoras , Regulación de la Expresión Génica/efectos de los fármacos , Genes Reporteros , Glutatión Transferasa/genética , VIH-1/genética , Humanos , Interleucina-1/farmacología , Interleucina-6/genética , Células Jurkat , FN-kappa B/metabolismo , Pruebas de Precipitina , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas/farmacología , Factor de Transcripción ReIA , Activación Transcripcional/efectos de los fármacos , Transfección , Factor de Necrosis Tumoral alfa/farmacología , LevadurasRESUMEN
Neuroglycan C (NGC) is a membrane-spanning chondroitin sulfate proteoglycan with an epidermal growth factor module that is expressed predominantly in the brain. Cloning studies with mouse NGC cDNA revealed the expression of three distinct isoforms (NGC-I, -II, and -III) in the brain and revealed that the major isoform showed 94. 3% homology with the rat counterpart. The NGC gene comprised six exons, was approximately 17 kilobases in size, and was assigned to mouse chromosome band 9F1 by fluorescence in situ hybridization. Western blot analysis demonstrated that, although NGC in the immature cerebellum existed in a proteoglycan form, most NGC in the mature cerebellum did not bear chondroitin sulfate chain(s), indicating that NGC is a typical part-time proteoglycan. Immunohistochemical studies showed that only the Purkinje cells were immunopositive in the cerebellum. In the immature Purkinje cells, NGC, probably the proteoglycan form, was immunolocalized to the soma and thick dendrites on which the climbing fibers formed synapses, not to the thin branches on which the parallel fibers formed synapses. This finding suggests the involvement of NGC in the differential adhesion and synaptogenesis of the climbing and parallel fibers with the Purkinje cell dendrites.
Asunto(s)
Cerebelo/crecimiento & desarrollo , Proteínas de la Membrana/genética , Proteoglicanos/genética , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Exones , Biblioteca de Genes , Biblioteca Genómica , Inmunohistoquímica , Hibridación Fluorescente in Situ , Masculino , Proteínas de la Membrana/biosíntesis , Proteínas de la Membrana/química , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Isoformas de Proteínas , Proteoglicanos/biosíntesis , Proteoglicanos/química , Células de Purkinje/química , Homología de Secuencia de Aminoácido , Distribución TisularRESUMEN
Using cDNA of human protocadherin 2A (pc2A; originally known as protocadherin 2) as a probe, we cloned a new member of the protocadherin 2 subfamily from mouse brain cDNA libraries and named it protocadherin 2C (pc2C). It was similar to pc2A throughout its entire coding region, and its C-terminal region was highly conserved. The locus of the pc2C gene was on the mouse chromosome 18C where the pc2A gene is located, suggesting that genes of the pc2 subfamily form a gene cluster. The expression of pc2C was restricted to the nervous system, and the expression started in the embryonic stage and increased up to the adult stage. The expression pattern was quite similar to that of OL-protocadherin, a distinct class of protocadherin, although the timing and relative strength of expression were different. These results suggest that pc2C may be involved in neural development along with other classes of protocadherins.
Asunto(s)
Encéfalo/embriología , Cadherinas/genética , Regulación del Desarrollo de la Expresión Génica , Secuencia de Aminoácidos , Animales , Encéfalo/crecimiento & desarrollo , Encéfalo/metabolismo , Cadherinas/química , Cromosomas/genética , Clonación Molecular , Ligamiento Genético , Humanos , Hibridación in Situ , Ratones , Datos de Secuencia Molecular , Mapeo Físico de Cromosoma , Protocadherinas , ARN Mensajero/genética , ARN Mensajero/metabolismo , Alineación de Secuencia , Homología de Secuencia de AminoácidoRESUMEN
Smad proteins are known to transduce signalling of TGF-beta receptor superfamily. We report here the entire sequences of rat Smad2 and Smad4 which have not been identified yet. Entire sequences were identified by degenerated polymerase chain reaction and following phage library screening and 5' RACE. The predicted amino acid sequences of rat Smad2 and Smad4 are highly conserved among rat, human and mouse. We also mapped these Smads to chromosome 18q.12.3. Unlike endothelial cells, TGF-beta1 stimulates articular chondrocyte proliferation as well as extracellular matrix production, and acts as a repairing agent against cartilage destruction. Since both Smad2 and Smad4 are essential factors for TGF-beta signalling, we examined their expression and regulation in cultured articular chondrocytes. Northern blot analysis showed that TGF-beta1 significantly increased the mRNA level of Smad2 but not of Smad4 in a dose- and time-dependent manner, suggesting that the augmentation of TGF-beta1 action is caused by increasing the expression of the downstream signalling molecule.
Asunto(s)
Cartílago Articular/metabolismo , Mapeo Cromosómico , Clonación Molecular , Proteínas de Unión al ADN/genética , Expresión Génica , Transactivadores/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Cartílago Articular/química , Condrocitos/química , Condrocitos/metabolismo , ADN Complementario/química , ADN Complementario/genética , Proteínas de Unión al ADN/química , Humanos , Masculino , Ratones , Datos de Secuencia Molecular , ARN Mensajero/análisis , Ratas , Ratas Sprague-Dawley , Receptores de Factores de Crecimiento Transformadores beta/metabolismo , Alineación de Secuencia , Transducción de Señal , Proteína Smad2 , Proteína Smad4 , Transactivadores/químicaRESUMEN
Mesomelic dysplasia Kantaputra type (MDK) (MIM *156232) is a new autosomal dominant skeletal dysplasia characterized by dwarfism, shortening of the forearms/lower-legs, carpal/tarsal synostosis, and dorsolateral foot deviation. We studied a Thai family in which 15 members in 3 generations were affected with MDK. With reference to the breakpoints of a balanced translocation [t(2;8)(q31;p21)] in patients from a previously reported Italian family with a skeletal dysplasia that appears similar to MDK, a linkage analysis was performed in the Thai family using 50 CA-repeat markers mapped to nearby regions (2q22-q34 and 8p24-p21) of the translocation breakpoints. The results clearly ruled out a linkage of MDK to marker loci at the 8p24-p21 region, whereas all nine affected members available for the study shared a haplotype at four loci (D2S2284, D2S326, D2S2188, and D2S2314) spanning about 22.7 cM in the 2q24-q32 region. The computer-assisted two-point linkage analysis revealed maximum logarithm of odds (lod) scores of 4.82, 4.21, 4.82, and 4.21 (theta = 0) at these loci, respectively. These data indicated that the MDK locus is in the vicinity of D2S2284 and D2S2188 loci that are most likely mapped to 2q24-q32.
Asunto(s)
Cromosomas Humanos Par 2/genética , Enanismo/genética , Mapeo Cromosómico , Femenino , Genes Dominantes , Ligamiento Genético , Haplotipos , Humanos , Masculino , LinajeRESUMEN
Neuroglycan C (NGC) is a 150 kDa transmembrane chondroitin sulfate proteoglycan with a 120 kDa core glycoprotein that was originally isolated from the developing rat brain. A rabbit antiserum, raised against a recombinant polypeptide representing a protein of the rat NGC core protein, recognized an NGC homolog in homogenates of brains of various vertebrates including humans. Because of the possible involvement of this proteoglycan in the etiology of a human neuronal disease, we cloned a complete coding sequence from a human brain cDNA library using a rat NGC cDNA as a probe. The predicted protein contains 539 amino acids and shows 86% homology with the rat counterpart. The domain structure characteristic of rat NGC was completely conserved in human NGC, which consisted of an N-terminal signal sequence, a chondroitin sulfate-attachment domain, an acidic amino acid cluster, an EGF-like domain, a transmembrane domain and a cytoplasmic tail. Northern blot analysis revealed that a single transcript of 2.4 kb was detectable in the brain, but not in other human tissues. By fluorescence in situ hybridization (FISH) analysis, the human NGC gene was assigned to the chromosomal 3p21.3 band, where the Sotos syndrome has been mapped. Involvement of the NGC gene in the etiology of the Sotos syndrome remains to be examined.