title: Two thioredoxin reductases, trxr-1 and trxr-2, have differential physiological roles in Caenorhabditis elegans.
abstract: Thioredoxin reductase (TrxR) is a member of the pyridine nucleotide-disulfide reductase family, which mainly functions in the thioredoxin system. TrxR is found in all living organisms and exists in two major ubiquitous isoenzymes in higher eukaryotic cells; One is cytosolic and the other mitochondrial. Mitochondrial TrxR functions to protect mitochondria from oxidative stress, where reactive oxidative species are mainly generated, while cytosolic TrxR plays a role to maintain optimal oxido-reductive status in cytosol. In this study, we report differential physiological functions of these two TrxRs in C. elegans. trxr-1, the cytosolic TrxR, is highly expressed in pharynx, vulva and intestine, whereas trxr-2, the mitochondrial TrxR, is mainly expressed in pharyngeal and body wall muscles. Deficiency of the non-selenoprotein trxr-2 caused defects in longevity and delayed development under stress conditions, while deletion mutation of the selenoprotein trxr-1 resulted in interference in acidification of lysosomal compartment in intestine. Interestingly, the acidification defect of trxr-1(jh143) deletion mutant was rescued, not only by selenocystein-containing wild type TRXR-1, but also cysteine-substituted mutant TRXR-1. Both trxr-1 and trxr-2 were up-regulated when worms were challenged by environmental stress such as heat shock. These results suggest that trxr-1 and trxr-2 function differently at organismal level presumably by their differential sub-cellular localization in C. elegans.
authors: Department of Life Science, Hanyang University, Seoul 133-791, Korea.
authors: Weixun
authors: W
authors: Li
authors: Jaya
authors: J
authors: Bandyopadhyay
authors: Hyun Sook
authors: HS
authors: Hwaang
authors: Byung-Jae
authors: BJ
authors: Park
authors: Jeong Hoon
authors: JH
authors: Cho
authors: Jin Il
authors: JI
authors: Lee
authors: Joohong
authors: J
authors: Ahnn
authors: Sun-Kyung
authors: SK
authors: Lee
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D007527:Isoenzymes; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D013880:Thioredoxin-Disulfide Reductase / Q000235:genetics / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D017382:Reactive Oxygen Species; D013880:Thioredoxin-Disulfide Reductase