Analysis of the Up-stream Region of SOX2, Embryonic Stem Cells Specific Gene, in the General Populntion

Abstract

Human embryonic stem cells (hESCs) are derived from the inner cell mass of the blastocyst, an early-stage embryo, which have the capability of differentiating into multiple cell lineages. Human embryonic stem cells posses the ability to self renew under appropriate conditions to give rise to equivalent daughter cells allowing indefinite propagation in culture. These characteristics make embryonic stem cells valuable tools in the scientific research, especially in regenerative therapy for treating a variety of human diseases. The undifferentiated state (ploripotency) of embryonic stem cells is maintained by the action of ES cell-specific transcription factors including OCT4, NANOG, and SOX2. These three factors bind to a large number of genes many of which are co- occupied by at least two of these three factors including the OCT4, NANOG, and SOX2 genes themselves, thus suggesting auto and reciprocal regulation amongst themselves. SOX2 can act synergistically with OCT314 to activate Ocl- Sox enhancers, which regulate the expression of pluripotent stem cell specific genes, including Nanog, OCT314 and SOX2 itself. Nanog, along with OCT4 and SOX2, are core transcription factors which regulate the pluripotency and self-renewal of embryonic stem cells. In vitro studies have shown that SOX2 is required by ES cells for its Oct- Sox enhancer activity and it is likely that, SOX2 is responsible for the activation of these Oct- Sox enhancers. Thus the essential function of SOX2 is to stabilize ES cells in a pluripotent state by maintaining the requisite level of OCTJI4 expression. This proves that these genes are crucial for the early human development. In present study upstream promoter region of SOX2 gene was analyzed for In present study upstream promoter region of SOX2 gene was analyzed for the existence of any sequence variant (polymorphism), in the two distinct population of Pakistan; Pakhtoon and Punjabi. Genomic DNA was extracted from blood samples collected from these individuals was PCR amplified by using specific primer set for the promoter region of SOX2 gene, followed by subsequent sequence analysis to find any sequence variant. Four out of 70 members showed a G to C transversion in the upstream promoter region of SOX2 while the remaining six members possessed normal sequence. Amplified DNA products in which sequence variant were detected were treated with specific restriction enzyme (PmeI) to confirm polymorphism. Agarose gel electrophoresis after 16 hours of enzyme treatment revealed that the restriction enzyme failed to digest the region in which variation was detected, suggesting that the Analysis of the Up-stream Region ofSOX2, Embryonic Stem Cells Specific Gene, in the General Population IX Abstract sequence variation was not a polymorphism, but a mistake in the DNA sequencing process. The lack of polymorphism shows that the sequence in the upstream promoter region of SOX2 gene is highly conserved and the evolution has not permitted any variation in this specific gene.