Synaptotagmin genes expression profiling in single pancreatic α and β-cell.

• Main Author: Tan, Sijie.
• Other Authors: Kristen Elizabeth Sadler
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Science::Biological sciences::Genetics
• Online Access: http://hdl.handle.net/10356/45261
• Institution: Nanyang Technological University

Gene expressions of synaptotagmins were characterized up to the resolution of pancreatic islets till date. However, it is unknown whether the synaptotagmin expressions identified were the results of α and/or β-cells transcription activities. Hence, we used a two-cycle multiplex and semi-nested PCR amplification procedure to first identify gene expressions of synaptotagmin isoforms I-X in mouse single pancreatic pseudo-islet, then increasing the resolution to single pancreatic α and β-cell. Our study detected the gene expressions of synaptotagmins V, VII and IX at the pseudo-islet level, and demonstrated that α-cells express synaptotagmins VII and IX, while β-cells express synaptotagmin VII. Based on the transcript abundance of synaptotagmin isoforms, we suggest that synaptotagmin VII is the principal Ca2+ sensor in Ca2+-dependent glucagon and insulin exocytosis in α and β-cells. We also characterized the gene expressions of synaptotagmin isoforms I-X in αTC-1 cells subjected to prolonged hyperglycemia, as a model to study synaptotagmin genes expression in pancreatic α-cells in Type II Diabetes Mellitus. We demonstrated that synaptotagmins III and VII genes expression were significantly up-regulated during hyperglycemia. Hence, we propose a hyperglycemia-induced stimulus-secretion coupling model in αTC-1 cells to account for this behaviour.