MUTATION OF THE VESICULAR MONOAMINE TRANSPORTER-1 GENE ALTERS ITS PROTEIN PRODUCT

Abstract

MUTATION OF THE VESICULAR MONOAMINE TRANSPORTER-1 GENE ALTERS ITS PROTEIN PRODUCT By Abena Watson-Siriboe, B.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Biology at Virginia Commonwealth University. Virginia Commonwealth University, 2010 Major Director: Jennifer K. Stewart Associate Professor and Graduate Director, Department of Biology The vesicular monoamine transporter 1 (VMAT1) is essential for storage of monoamines, such as epinephrine and serotonin, in secretory vesicles of neuroendocrine cells. Recently the VMAT1 protein was detected in human and mouse brain, and mutations of the VMAT1 gene at single DNA nucleotides (single nucleotide polymorphisms or SNPs) were associated with schizophrenia. In this study, Chinese hamster ovarian cells were stably transfected with either human VMAT1 DNA (GenBank: #NM_003053.1) or DNA with the Thr4Pro SNP, which results in a threonine to proline change in amino acid number 4 of the VMAT1 protein. Western blot analysis revealed that cells with the SNP produced immunoreactive human VMAT1 proteins of altered molecular size, suggesting that SNP Thr4Pro modifies either folding or processing of the VMAT1 protein. This finding is the first evidence for biochemical consequences of a mutation in the human VMAT1 gene.