Molecular Cloning of Suncus Gastrointestinal Hormone Gene

Glucagon is a hormone that is produced by alpha cells in the islets of Langerhans of the pancreas which raises blood glucose levels. The effects of glucagon are the opposite of the effects induced by insulin. The two hormones work as feedback mechanism to balance the blood glucose levels. In the present study, to sequence the glucagon in the house musk shrew (Suncus murinus, order: Insectivora, suncus is used as a laboratory name), we extracted RNA from the samples of Suncus for cloning. The cDNA was formed by the process of Reverse Transcription PCR followed by Primer Designing. The designed primers FW1, RV1, FW2 and RV2 were used for Nested PCR. 3′ RACE was performed to synthesize and amplify the glucagon hormone. The formed sequence was then inserted into the pGEM T Easy Vector using T4 DNA Ligase enzyme. The inserted Glucogon was sequenced in Genetic Analyzer. The result from the present study can work as a new approach to treat diseases related to Blood sugar level by the formation of Pharmacological Drug (Modified Glucagon Tablets).
Glucagon-producing alpha cells represent one of the earliest populations of detectable islet cells in the developing endocrine pancreas. Glucagon isa hormone that opposes the action of insulin in peripheral tissues, predominantly the liver, where the insulin:glucagonratio determines the intricate control of gluconeogenesis and glycogenolysis. Glucose is stored in the liver in the form of glycogen, which is a starch-like polymer chain made up of glucose molecules. Liver cells (hepatocytes) have glucagon receptors. When glucagon binds to the glucagon receptors, the liver cells convert the glycogen polymer into individual glucose molecules, and release them into the bloodstream, in a process known as glycogenolysis. As these stores become depleted, glucagon then encourages the liver to synthesize additional glucose by gluconeogenesis. Glucagon turns off glycolysis in the liver, causing glycolytic intermediates to be shuttled to gluconeogenesis.
Glucagon, a peptide of 29 amino acids that is produced and secreted by the pancreas, is a regulator of carbohydrate and protein metabolism(Gerhard Heinrich, Philippe GrosS and Joel F. Habener, 1984). Haber et.al. recently, determined the nucleotide sequence of mRNA of 1300 nucleotides that encodes rat pre-proglucagon, a polyprotein precursor of glucagon.James W.White and Grady F.Saunders (1986) concluded that a clone containing the complete human glucagon gene was isolated and sequenced. The gene is approximately 9.4 kilobases in length and comprises six exons and five introns.
In this study, we focused on the house musk shrew (Suncus murinus), suncus is used as a laboratory name, as a model animal. Suncus is known to be a primitive mammal belonging to the order Insectivora and has recently been established as a novel animal for the study of motilin. In this study, we determined the partial sequence of Glucagon cDNA and the structure of the partial peptide in the Suncus.