Glucose uptake kinetics and transcription of HXT genes chemostat cultures of Saccharomyces cerevisiae
Glucose uptake kinetics and transcription of HXT genes chemostat cultures of Saccharomyces cerevisiae
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DOI：
10.1074/jbc.274.22.15350
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发表时间：
1999-05-28
影响因子：
4.8
通讯作者：
Kruckeberg, AL
中科院分区：
文献类型：
--
作者：
Diderich, JA;Schepper, M;Kruckeberg, AL
葡萄糖转运的动力学和HXT己糖转运蛋白基因家族的所有20个成员的转录与在恒化器培养物中生长的酿酒酵母CEN.PK113- 7 D的稳态原位碳代谢有关。在各种营养限制条件下（厌氧葡萄糖或氮限制或需氧葡萄糖、半乳糖、果糖、乙醇或氮限制）以0.10 h（-1）的稀释率培养细胞，或在需氧葡萄糖限制培养物中以0.05 - 0.38 h（-1）的稀释率培养细胞。HXT 1-HXT 7的转录与培养物中的胞外葡萄糖浓度相关。GAL 2的转录，编码半乳糖转运蛋白，仅在半乳糖限制的文化中检测到。SNF 3和RGT 2是HXT家族中编码葡萄糖传感器的两个成员，其转录水平较低。HXT 8-HXT 17转录本的检测水平非常低。单个HXT基因的表达和5 s内C-14-葡萄糖的零反式内流测定的葡萄糖转运动力学之间观察到一致的关系，这种关系与先前对单个HXT菌株的研究中推导的Hxt 1-Hxt 7和Gal 2的转运动力学广泛一致。在较低的稀释率的葡萄糖转运能力估计从零反式流入实验和残留的葡萄糖浓度超过了测量的原位葡萄糖消耗率。然而，在高稀释率下，估计的葡萄糖转运能力太低，无法解释原位葡萄糖消耗速率。
The kinetics of glucose transport and the transcription of all 20 members of the HXT hexose transporter gene family were studied in relation to the steady state in situ carbon metabolism of Saccharomyces cerevisiae CEN.PK113-7D grown in chemostat cultures. Cells were cultivated at a dilution rate of 0.10 h(-1) under various nutrient-limited conditions (anaerobically glucose- or nitrogen-limited or aerobically glucose-, galactose-, fructose-, ethanol-, or nitrogen-limited), or at dilution rates ranging between 0.05 and 0.38 h(-1) in aerobic glucose-limited cultures. Transcription of HXT1-HXT7 was correlated with the extracellular glucose concentration in the cultures. Transcription of GAL2, encoding the galactose transporter, was only detected in galactose-limited cultures. SNF3 and RGT2, two members of the HXT family that encode glucose sensors, were transcribed at low levels. HXT8-HXT17 transcripts were detected at very low levels. A consistent relationship was observed between the expression of individual HXT genes and the glucose transport kinetics determined from zero-trans influx of C-14-glucose during 5 s, This relationship was in broad agreement with the transport kinetics of Hxt1-Hxt7 and Gal2 deduced in previous studies on single-HXT strains. At lower dilution rates the glucose transport capacity estimated from zero-trans influx experiments and the residual glucose concentration exceeded the measured in situ glucose consumption rate. At high dilution rates, however, the estimated glucose transport capacity was too low to account for the in situ glucose consumption rate.