Uchiyama Junji, Asakura Ryosuke, Moriyama Atsushi, Kubo Yuko, Shibata Yousuke, Yoshino Yuka, Tahara Hiroko, Matsuhashi Ayumi, Sato Shusei, Nakamura Yasukazu, Tabata Satoshi, Ohta Hisataka
Research Center for RNA Science, RIST, Tokyo University of Science, Noda, Chiba 278-8510, Japan.
Department of Biology, Faculty of Science, Tokyo University of Science, Shinjuku, Tokyo 162-8601, Japan.
Plant Physiol Biochem. 2014 Aug;81:36-43. doi: 10.1016/j.plaphy.2014.02.007. Epub 2014 Feb 21.
In this study, the genes expressed in response to low pH stress were identified in the unicellular cyanobacterium Synechocystis sp. PCC 6803 using DNA microarrays. The expression of slr0967 and sll0939 constantly increased throughout 4-h acid stress conditions. Overexpression of these two genes under the control of the trc promoter induced the cells to become tolerant to acid stress. The Δslr0967 and Δsll0939 mutant cells exhibited sensitivity to osmotic and salt stress, whereas the trc mutants of these genes exhibited tolerance to these types of stress. Microarray analysis of the Δslr0967 mutant under acid stress conditions showed that expression of the high light-inducible protein ssr2595 (HliB) and the two-component response regulator slr1214 (rre15) were out of regulation due to gene inactivation, whereas they were upregulated by acid stress in the wild-type cells. Microarray analysis and real-time quantitative reverse transcription-polymerase chain reaction analysis showed that the expression of sll0939 was significantly repressed in the slr0967 deletion mutant. These results suggest that sll0939 is directly involved in the low pH tolerance of Synechocystis sp. PCC 6803 and that slr0967 may be essential for the induction of acid stress-responsive genes.
在本研究中，利用DNA微阵列技术在单细胞蓝藻集胞藻PCC 6803中鉴定了响应低pH胁迫表达的基因。在4小时的酸胁迫条件下，slr0967和sll0939的表达持续增加。在trc启动子控制下过表达这两个基因可诱导细胞对酸胁迫产生耐受性。Δslr0967和Δsll0939突变细胞对渗透胁迫和盐胁迫敏感，而这些基因的trc突变体对这些类型的胁迫具有耐受性。对酸胁迫条件下的Δslr0967突变体进行微阵列分析表明，由于基因失活，高光诱导蛋白ssr2595（HliB）和双组分响应调节因子slr1214（rre15）的表达失调，而在野生型细胞中它们被酸胁迫上调。微阵列分析和实时定量逆转录-聚合酶链反应分析表明，sll0939的表达在slr0967缺失突变体中受到显著抑制。这些结果表明，sll0939直接参与集胞藻PCC 6803对低pH的耐受性，并且slr0967可能对酸胁迫响应基因的诱导至关重要。
