Roles of cold-inducible chaperones in hyperthermophiles

有人认为，超嗜热菌是高度原始的微生物，它们的后代是通过适应较冷的环境而进化的。因此，研究超嗜热生物对寒冷环境的适应机制可能有助于深入了解进化过程。在该项目中，研究了来自Thermococcus kodakarensis的冷诱导伴侣cpkA（TK0678）和DEAD box RNA解旋酶（TK0306）的生理作用，表明这两个基因对于冷应激环境下的细胞生长至关重要。此外，还确定了TK0306冷诱导所需的区域。 调节元件（五腺苷序列）位于 SD 区和起始密码子 (ATG) 之间的区域。 A5 依赖性冷诱导表达似乎与取决于温度的提前终止有关。 这种序列特异性机制是独特的，并且在其他已知的冷诱导基因中尚未发现。

It has been suggested that hyperthermophiles are highly primitive microorganisms and that their descendents evolved by adapting to cooler environments. Hence, study of the adaptive mechanisms of hyperthermophiles to cold environments may provide insight into evolutionary processes. In the project, the physiological roles of cold inducible chaperones, cpkA (TK0678) and DEAD box RNA helicase (TK0306) from Thermococcus kodakarensis were investigated, showing that both genes are essential for cell growth at cold stressed environment. In addition, the region required for cold induction of TK0306 was identified. The regulatory element, a five-adenosine sequence has been located in the region between the SD region and the initiation codon (ATG). It seems likely that A5 -dependent cold-induced expression is related to premature termination depending on temperature. This sequence-specific mechanism is unique, and one that has not been identified in other known cold-inducible genes.