Piper P W, Curran B, Davies M W, Hirst K, Lockheart A, Seward K
Department of Biochemistry, University College, London, UK.
Mol Microbiol. 1988 May;2(3):353-61. doi: 10.1111/j.1365-2958.1988.tb00039.x.
Heat shock enhances the very high level of transcription of the phosphoglycerate kinase (PGK) gene in fermentative cultures of Saccharomyces cerevisiae. This response of PGK mRNA levels was not found on gluconeogenic carbon sources, and could be switched on or off subject to availability of fermentable carbon source. The addition of glucose to yeast growing on glycerol resulted in acquisition, within 30-60 min, of the ability to elevate PGK mRNA levels after heat shock. In addition, in aerobic cultures growing on glucose the exhaustion of the medium glucose coincided with a loss of the heat-shock effect on PGK mRNA and a switch-over to slower growth by aerobic respiration. Levels of hsp26 mRNA were analysed during these experiments. Contrasting with this requirement for fermentable catabolite for manifestation of a heat-shock response of PGK mRNA levels, the PGK enzyme was not synthesized at a greater level in heat-shocked fermentative than in gluconeogenic cultures. PGK is one of only a few proteins made efficiently after mild heat shock of yeast. Thus, heat-stress-induced elevation of PGK mRNA levels does not appreciably increase PGK synthesis during exposure to high temperatures and so its role may be to assist cells repressed in mitochondrial function during recovery following a heat shock.
热休克可增强酿酒酵母发酵培养物中磷酸甘油酸激酶（PGK）基因的高水平转录。在糖异生碳源上未发现PGK mRNA水平的这种反应，并且其可根据可发酵碳源的可用性开启或关闭。向在甘油上生长的酵母中添加葡萄糖，会使其在热休克后30 - 60分钟内获得提高PGK mRNA水平的能力。此外，在以葡萄糖为碳源的需氧培养物中，培养基中葡萄糖耗尽时，对PGK mRNA的热休克效应丧失，细胞转而通过有氧呼吸进行较慢的生长。在这些实验中分析了hsp26 mRNA的水平。与PGK mRNA水平热休克反应的表现需要可发酵分解代谢物不同，热休克的发酵培养物中PGK酶的合成水平并不比糖异生培养物中更高。PGK是酵母轻度热休克后仅能高效合成的少数几种蛋白质之一。因此，热应激诱导的PGK mRNA水平升高在高温暴露期间不会明显增加PGK的合成，所以其作用可能是帮助热休克后恢复过程中线粒体功能受抑制的细胞。
