Cellular functions and transcriptional regulation of a third thioredoxin from Schizosaccharomyces pombe.
The structural gene encoding a third thioredoxin (Trx) homologue, TRX3, of the fission yeast Schizosaccharomyces pombe was characterized and its regulation was studied. The determined DNA sequence encoded a putative 290 amino acid sequence of Trx with a molecular mass of 31,889 Da. The TRX3 mRNA level was increased in S. pombe cells harboring plasmid pTRX3, suggesting that the cloned TRX3 gene was functional. Yeast cultures harbouring plasmid pTRX3 exhibited shorter generation times and higher survival on solid minimal media plates incorporating mercury chloride (0.01 mmol/L) or hydrogen peroxide (1 mmol/L) compared with control cultures. Yeast cells containing extra copies of TRX3, but not TRX1 and TRX2, gave rise to lower reactive oxygen species levels than control cells. Oxidative stress owing to hydrogen peroxide and menadione enhanced the synthesis of beta-galactosidase from the TRX3-lacZ fusion gene in Pap1-positive cells but not in Pap1-negative cells. The TRX3 mRNA level was increased by oxidative stress only in Pap1-positive cells. Basal expression of the TRX3 gene also depended on Pap1. We concluded that S. pombe TRX3 is linked with yeast growth and oxidative stress response, with its expression being regulated by oxidative stress in a Pap1-dependent manner.
Kim
Su-Jung
SJ
Division of Life Sciences and Research Institute of Life Sciences, Kangwon National University, Chuncheon 200-701, Korea.
Jung
Eui-Man
EM
Jung
Hyun-Joo
HJ
Song
Yun Seon
YS
Park
Eun-Hee
EH
Lim
Chang-Jin
CJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D005434:Flow Cytometry; D015966:Gene Expression Regulation, Fungal; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D000073718:Pancreatitis-Associated Proteins; D017433:Protein Structure, Secondary; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology
D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; D017382:Reactive Oxygen Species; D029702:Schizosaccharomyces pombe Proteins; D013879:Thioredoxins