Role of transcriptional regulation in controlling fluxes in central carbon metabolism of Saccharomyces cerevisiae -: A chemostat culture study
Role of transcriptional regulation in controlling fluxes in central carbon metabolism of Saccharomyces cerevisiae -: A chemostat culture study
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DOI：
10.1074/jbc.m309578200
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发表时间：
2004-03-05
影响因子：
4.8
通讯作者：
Pronk, JT
中科院分区：
文献类型：
--
作者：
Daran-Lapujade, P;Jansen, MLA;Pronk, JT
与批量培养相比，恒化培养可以识别碳源响应，而不受碳分解代谢物抑制、有毒产物积累和特定生长速率差异的干扰。这项研究的重点是酵母酿酒酵母，生长在有氧，碳限制的化学调节培养。比较了两种糖（葡萄糖和麦芽糖）以及两种c2化合物（乙醇和醋酸盐）的生长情况下全基因组转录水平和体内通量。与之前关于批量培养的报道相比，很少有基因（180个基因）通过改变转录物水平来响应碳源的变化。当葡萄糖作为生长限制营养素与麦芽糖（33个转录本）相比时，或当乙酸与乙醇（16个转录本）相比时，转录本水平几乎没有变化。尽管使用化学计量模型的代谢通量分析揭示了中心碳代谢的主要变化，但当提供糖和c2化合物作为生长限制营养素时，只有117个基因表现出显著不同的转录水平。尽管对酵母的碳源调控有广泛的了解，但许多碳源响应基因编码的蛋白质具有未知或不完全表征的生物学功能。碳源响应基因的启动子分析证实了几个已知的转录调控因子的参与，并提出了其他调控因子的参与。参与乙醛酸循环和糖异生的转录本显示出与体内通量的良好相关性。然而，在其他重要的途径中没有观察到这种相关性，包括戊糖-磷酸途径、三羧酸循环，尤其是糖酵解。这些结果表明，在稳定状态下生长的酿酒酵母体内中心碳代谢通量在很大程度上是通过转录后机制控制的。
In contrast to batch cultivation, chemostat cultivation allows the identification of carbon source responses without interference by carbon-catabolite repression, accumulation of toxic products, and differences in specific growth rate. This study focuses on the yeast Saccharomyces cerevisiae, grown in aerobic, carbon-limited chemostat cultures. Genome-wide transcript levels and in vivo fluxes were compared for growth on two sugars, glucose and maltose, and for two C2-compounds, ethanol and acetate. In contrast to previous reports on batch cultures, few genes ( 180 genes) responded to changes of the carbon source by a changed transcript level. Very few transcript levels were changed when glucose as the growth-limiting nutrient was compared with maltose ( 33 transcripts), or when acetate was compared with ethanol ( 16 transcripts). Although metabolic flux analysis using a stoichiometric model revealed major changes in the central carbon metabolism, only 117 genes exhibited a significantly different transcript level when sugars and C2-compounds were provided as the growth-limiting nutrient. Despite the extensive knowledge on carbon source regulation in yeast, many of the carbon source-responsive genes encoded proteins with unknown or incompletely characterized biological functions. In silico promoter analysis of carbon source-responsive genes confirmed the involvement of several known transcriptional regulators and suggested the involvement of additional regulators. Transcripts involved in the glyoxylate cycle and gluconeogenesis showed a good correlation with in vivo fluxes. This correlation was, however, not observed for other important pathways, including the pentose-phosphate pathway, tricarboxylic acid cycle, and, in particular, glycolysis. These results indicate that in vivo fluxes in the central carbon metabolism of S. cerevisiae grown in steadystate, carbon-limited chemostat cultures are controlled to a large extent via post-transcriptional mechanisms.