title: Vanderwaltozyma polyspora possesses two glycyl-tRNA synthetase genes: one constitutive and one inducible.
abstract: Aminoacyl-tRNA synthetases are housekeeping enzymes essential for protein synthesis. We herein present evidence that the yeast Vanderwaltozyma polyspora possesses two paralogous glycyl-tRNA synthetase (GlyRS) genes-GRS1 and GRS2. Paradoxically, GRS1 provided functions in both the cytoplasm and mitochondria, while GRS2 was essentially silent under normal growth conditions. Expression of GRS2 could be activated by stresses such as high pH or ethanol and most effectively by high temperature. The expressed GlyRS2 protein was exclusively found in the cytoplasm and more stable under heat-shock conditions (37°C) than under normal growth conditions (30°C) in vivo. In addition, GRS2 effectively rescued the cytoplasmic defect of a Saccharomyces cerevisiae GRS1 knockout strain when expressed from a constitutive promoter. Moreover, the purified GlyRS2 enzyme was fairly active at both 30°C and 37°C in glycylation of yeast tRNA in vitro. However, unexpectedly, the purified GlyRS2 enzyme was practically inactive at temperature above 40°C in vitro. Our study suggests that GRS2 is an inducible gene that acts under stress conditions where GlyRS1 may be insufficient, unavailable, or rendered inactive.
authors: Department of Life Sciences, National Central University, 300 Jung-da Rd., Jung-li 32001, Taiwan.
authors: Chin-I
authors: CI
authors: Chien
authors: Department of Life Sciences, National Central University, 300 Jung-da Rd., Jung-li 32001, Taiwan.
authors: Yueh-Lin
authors: YL
authors: Chen
authors: Department of Life Sciences, National Central University, 300 Jung-da Rd., Jung-li 32001, Taiwan.
authors: Shun-Jia
authors: SJ
authors: Chen
authors: Department of Life Sciences, National Central University, 300 Jung-da Rd., Jung-li 32001, Taiwan.
authors: Chi-Mao
authors: CM
authors: Chou
authors: Department of Life Sciences, National Central University, 300 Jung-da Rd., Jung-li 32001, Taiwan.
authors: Chin-Yu
authors: CY
authors: Chen
authors: Department of Life Sciences, National Central University, 300 Jung-da Rd., Jung-li 32001, Taiwan. Electronic address: dukewang@cc.ncu.edu.tw.
authors: Chien-Chia
authors: CC
authors: Wang
mesh_terms: D000595:Amino Acid Sequence; D001203:Ascomycota / Q000145:classification / Q000201:enzymology* / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D006032:Glycine-tRNA Ligase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D018869:Heat-Shock Response; D008969:Molecular Sequence Data
chemical_list: D006032:Glycine-tRNA Ligase
keywords: Aminoacyl-tRNA synthetase; Constitutive gene; Dual function; Inducible gene; Stress