Asst. Prof. Dr. Sarawut Jitrapakdee Thailand Young Scientist Award Year 2003   Dr. Sarawut Jitrapakdee has been working on two unrelated areas. The first one is the molecular biology study of the yellow head virus (YHV), one of the major viral agents causing mass mortalities and heavy production losses in farmed shrimp. He has been interested in the envelope glycoproteins as these proteins are associated with the entry of virus into host cells, and mediate host immune response. The glycoproteins of YHV have been found to be synthesized as a polyprotein which undergoes glycosylation and proteolytic processing to produce two distinct glycoproteins i.e. gp116 and gp64. This finding leads to the development of a baculovirus/insect expression system to produce the soluble gp64 glycoprotein that will be useful for structure/function studies. In addition, he has been trying to identify a series of genes that are turned on and off in shrimps upon infection by the viruses. The information obtained from these studies will be extremely useful for the prevention of YHV infection.   Dr. Jitrapakdee has also studied the regulation of pyruvate carboxylase in pancreatic islets. This enzyme plays an important role in gluconeogenesis, lipogenesis in liver and adipose tissue, respectively and in glucose-induced insulin secretion in b-cells. Obesity and Type 2 diabetes are also associated with the abnormal expresson of the enzyme. Studies on the structure and organization of this enzyme in several mammalian species revealed that gene encoding this enzyme possesses two tissue-specific promoters that are differentialy regulated. The b-cells-specific promoter was affectd by glucose and free fatty acids. Under basal conditions this promoter is predominantly regulated by two transcription factors, Sp1 and NF-Y. He is currently identifying tissue-specific factors that could mediate glucose and fatty acid responses in b-cells.