Dissertation/Thesis Abstract

ENV9, a novel gene in Saccharomyces cerevisiae, is responsible for the pleiotropic phenotype of env9Δ and encodes a membrane protein that is localized to lipid droplets
by Hsueh, Teli, M.S., California State University, Long Beach, 2012, 88; 1522232
Abstract (Summary)

Over the past several decades, many characterizations in vesicular trafficking system have led to great understanding of the endomembrane system, and several genetic screens have identified mutants defective in various protein sorting and trafficking functions within this system. Recently, a newly characterized group of mutants from our laboratory was reported to exhibit internal accumulation of the precursor carboxypeptidase (proCPY), at the post-endosome to vacuole trafficking stage, and named the late endosome and vacuole interface, or env mutants. The result from the screen has revealed a group of novel genes that have no previously established functions including ENV9. ENV9 is 993 base pairs in length, and encodes a protein of 330 amino acids (40 kDa) with homology to oxidoreductases. env9Δ mutant is caffeine sensitive, and exhibits an unusual vacuolar morphology, where accumulation of vesicles in the vacuole is observed. Env9 protein has also been reported to be localized to lipid droplets (LDs) from a systematic study. In this study, more research results were established on ENV9, its mutant, and its encoded protein. Further characterizations of the phenotypic traits of env9Δ mutant shows normal vacuolar acidification and autophagy function. The kinetics of CPY processing reveals a delay in maturation. Complementation of ENV9 in env9Δ mutant confirms that the deletion of the gene is responsible for the pleiotropic phenotype, while overexpression of the gene has no effects on vacuolar and LD morphologies, and caffeine sensitivity. Fluorescence microscopy on subcellular colocalization of GFP-tagged Env9p and Nile Red signal confirms that Env9p is localized to LDs. Biochemical assay using HA-tagged Env9p shows that it is membrane associated.

Indexing (document details)
Advisor: Gharakhanian, Editte
Commitee: Livingston, Brian, McAbee, Douglas
School: California State University, Long Beach
Department: Biological Sciences
School Location: United States -- California
Source: MAI 51/05M(E), Masters Abstracts International
Subjects: Biology, Molecular biology, Cellular biology
Publication Number: 1522232
ISBN: 978-1-267-97720-5
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