Saccharomyces cerevisiae ER membrane protein complex subunit 4 (EMC4) plays a crucial role in eIF2B-mediated translation regulation and survival under stress conditions.
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ABSTRACT: BACKGROUND:Eukaryotic initiation factor 2B (eIF2B) initiates and regulates translation initiation in eukaryotes. eIF2B gene mutations cause leukoencephalopathy called vanishing white matter disease (VWM) in humans and slow growth (Slg-) and general control derepression (Gcd-) phenotypes in Saccharomyces cerevisiae. RESULTS:To suppress eIF2B mutations, S. cerevisiae genomic DNA library was constructed in high-copy vector (YEp24) and transformed into eIF2B mutant S. cerevisiae strains. The library was screened for wild-type genes rescuing S. cerevisiae (Slg-) and (Gcd-) phenotypes. A genomic clone, Suppressor-I (Sup-I), rescued S. cerevisiae Slg- and Gcd- phenotypes (gcd7-201 gcn2?). The YEp24/Sup-I construct contained truncated TAN1, full length EMC4, full length YGL230C, and truncated SAP4 genes. Full length EMC4 (chaperone protein) gene was sub-cloned into pEG (KG) yeast expression vector and overexpressed in gcd7-201 gcn2? strain which suppressed the Slg- and Gcd- phenotype. A GST-Emc4 fusion protein of 47?kDa was detected by western blotting using ?-GST antibodies. Suppression was specific to gcd7-201 gcn2? mutation in eIF2B? and Gcd1-502 gcn2? in eIF2B? subunit. Emc4p overexpression also protected the wild type and mutant (gcd7-201 gcn2?, GCD7 gcn2?, and GCD7 GCN2?) strains from H2O2, ethanol, and caffeine stress. CONCLUSIONS:Our results suggest that Emc4p is involved in eIF2B-mediated translational regulation under stress and could provide an amenable tool to understand the eIF2B-mediated defects.
SUBMITTER: Sharma S
PROVIDER: S-EPMC7261713 | biostudies-literature | 2020 Jun
REPOSITORIES: biostudies-literature
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