Class III Malocclusion: Missense Mutations in DUSP6 Gene

Objective: To determine the DUSP6 gene mutation in three generations of Malaysian Malay subjects having Class III malocclusion. Material and Methods: Genetic analyses of DUSP6 gene were carried out in 30 subjects by selecting three individuals representing three generations, respectively, from ten Malaysian Malay families having Class III malocclusion and 30 healthy controls. They were submitted Clinical Evaluation to clinical examination, lateral cephalometric radiographs, dental casts, and/ or facial and intra-oral photographs. Buccal cell was taken from each participant of Class III malocclusion and control groups. DNA extractions from buccal cell were carried out using Gentra puregene buccal cell kit. Bio Edit Sequence Alignment Editor software was used to see the sequencing result. Results: A heterozygous missense mutation c.1094C>T (p. Thr 365 Ile) was identified in DUSP6 gene in three members of one family with Class III malocclusion, whereas no mutation was found in the control group. Conclusion: Current study successfully identified a missense mutation in DUSP6 gene among one Malaysian Malay family affected by Class III malocclusion. The outcome of this study broadened the mutation spectrum of Class III malocclusion and the importance of DUSP6 gene in skeletal functions.

Expression analysis of notsh signaling pathway molecules in shed cultured in keratinocyte growth medium

Aim: To detect the expression of molecules associated with Notch signaling pathway in stem cells from human exfoliated deciduous teeth (SHED) cultured in specific differentiation medium, namely, keratinocyte growth medium (KGM). Methods:RNA was extracted from SHED harvested on day 1, 3 and 7. RNA was reverse-transcribed to obtain the cDNA and then proceeded with PCR using specific primers for the Notch signaling pathway molecules (Notch1, Jagged-1, Jagged-2 and, Hes1) as well as stem cell marker (Nanog). PCR products were electrophoresed on a 2% agarose gel and stained with SYBR green. Results:Notch-1 was highly expressed in SHED cultured in KGM and showed increase in density as the days progressed, while Jagged-1 showed a decrease. Jagged-2 on the other hand, showed a slight increase on day 3 followed by a decrease on day 7. However, Hes-1 was not expressed in SHED cultured in KGM. Nanog showed expression only on day 3 and gradually increased in expression on day 7. Conclusions:Notch signaling pathway associated molecules; Notch-1, Jagged-1, Jagged-2, and stem cell marker Nanog are expressed in SHED cultured in KGM which may be involved in the differentiation into epithelial-like cells in human dental pulp tissues.

Extraction of mitochondrial DNA from tooth dentin: application of two techniques

Mitochondrial DNA (mtDNA) is a hereditary material located in mitochondria and is normally maternally inherited. Mutational analysis performed on mtDNA proved that the mutations are closely related with a number of genetic illnesses, besides being exploitable for forensic identification. Those findings imply the importance of mtDNA in the scientific field. MtDNA can be found in abundance in tooth dentin where it is kept protected by the enamel, the hardest outer part of the tooth. In this study, two techniques of mtDNA extraction were compared to determine the efficacy between the two techniques. Teeth used for the study was collected from Dental Clinic, Hospital Universiti Sains Malaysia. After the removal of tooth from the tooth socket of the patient, the tooth was kept at -20C until use. Later, pulp tissue and enamel was excised using dental bur and only the root dentin was utilized for the isolation of mtDNA by crushing it mechanically into powdered form. MtDNA was extracted using the two published methods, Pfeifer and Budowle and then subjected to spectrophotometry DNA quantification and purity, Polymerase chain reaction (PCR) amplification of hypervariable-two region of mtDNA, followed by DNA sequencing to analyze the reliability of the extraction techniques. In conclusion, both techniques proved to be efficient and capable for the extraction of mtDNA from tooth dentin.