Suzuki I, Kanesaki Y, Mikami K, Kanehisa M, Murata N
Department of Regulation Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan.
Mol Microbiol. 2001 Apr;40(1):235-44. doi: 10.1046/j.1365-2958.2001.02379.x.
A histidine kinase, Hik33, appears to sense decreases in temperature and to regulate the expression of certain cold-inducible genes in the cyanobacterium Synechocystis sp. PCC6803. To examine the role of Hik33 in the regulation of gene expression, we analysed a DeltaHik33 mutant using the DNA microarray technique. In wild-type cells, genes that were strongly induced at low temperature encoded proteins that were predominantly subunits of the transcriptional and translational machinery. Most cold-repressible genes encoded components of the photosynthetic machinery. Mutation of the hik33 gene suppressed the expression of some of these cold-regulated genes, which could be divided into three groups according to the effect of the mutation of hik33. In the first group, regulation of gene expression by low temperature was totally abolished; in the second group, the extent of such regulation was reduced by half; and, in the third group, such regulation was totally unaffected. These results suggest that expression of the genes in the first group is regulated solely by Hik33, expression of genes in the third group is regulated by an as yet unidentified cold sensor, and expression of genes in the second group is regulated by both these cold sensors.
一种组氨酸激酶Hik33似乎能感知温度下降，并调节蓝藻集胞藻PCC6803中某些冷诱导基因的表达。为了研究Hik33在基因表达调控中的作用，我们使用DNA微阵列技术分析了一个Hik33缺失突变体。在野生型细胞中，在低温下强烈诱导的基因编码的蛋白质主要是转录和翻译机制的亚基。大多数冷抑制基因编码光合机制的组成部分。hik33基因突变抑制了其中一些冷调控基因的表达，根据hik33基因突变的影响，这些基因可分为三组。在第一组中，低温对基因表达的调控完全被消除；在第二组中，这种调控的程度减半；而在第三组中，这种调控完全不受影响。这些结果表明，第一组基因的表达仅由Hik33调控，第三组基因的表达由一个尚未确定的冷感受器调控，第二组基因的表达由这两种冷感受器共同调控。
