A gene cluster that regulates both heterocyst differentiation and pattern formation in Anabaena sp strain PCC 7120
A gene cluster that regulates both heterocyst differentiation and pattern formation in Anabaena sp strain PCC 7120
复制标题
调节鱼腥藻异形细胞分化和模式形成的基因簇。
DOI：
10.1111/j.1365-2958.2007.05997.x
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发表时间：
2007-12-01
影响因子：
3.6
通讯作者：
Xu, Xudong
中科院分区：
文献类型：
--
作者：
Zhang, Wei;Du, Ye;Xu, Xudong
野生型鱼腥藻菌株PCC 7120是一种丝状固氮蓝藻，以半规则的间隔产生单个异形胞。asr 0100（patU 5）和alr 0101（patU 3）与点状念珠藻的帕图的5'和3'部分同源。alr 0099（hetZ）与patU 5的5'端重叠。hetZ、patU 5和patU 3在原异形胞和异形胞中均上调或特异表达。hetZ突变体显示异形胞分化延迟或没有异形胞分化。相比之下，patU 3突变产生了多个连续的异形胞（Mch）表型，并恢复了形成，否则失去了intercalary异形胞在patA背景。降低patU 3的表达大大增加了mini-patS菌株中异形胞的频率。在hetZ-patU 5-patU 3区域检测到两个启动子区域和两个主要的相应转录物。hetZ的转录在hetZ突变体中上调，在patU 3突变体中下调。当突变体hetZ：：C.K2和hetZ：：Tn 5 - 1087 b被氮剥夺时，P-hetC-gfp非常弱地表达，并且在hetZ：：Tn 5 - 1087 b中，P-hetR-gfp在既没有规则模式也没有改变的形态的细胞中相对强地表达。我们的结论是hetZ-patU 5-patU 3簇起着重要的作用，在协调异形胞分化和模式的形成。没有异形胞的丝状属中的同源簇的存在是一个更普遍的作用暗示。
Wild-type Anabaena sp. strain PCC 7120, a filamentous nitrogen-fixing cyanobacterium, produces single heterocysts at semi-regular intervals. asr0100 (patU5) and alr0101 (patU3) are homologous to the 5' and 3' portions of patU of Nostoc punctiforme. alr0099 (hetZ) overlaps the 5' end of patU5. hetZ, patU5 and patU3 were all upregulated, or expressed specifically, in proheterocysts and heterocysts. Mutants of hetZ showed delayed or no heterocyst differentiation. In contrast, a patU3 mutation produced a multiple contiguous heterocyst (Mch) phenotype and restored the formation of otherwise lost intercalary heterocysts in a patA background. Decreasing the expression of patU3 greatly increased the frequency of heterocysts in a mini-patS strain. Two promoter regions and two principal, corresponding transcripts were detected in the hetZ-patU5-patU3 region. Transcription of hetZ was upregulated in a hetZ mutant and downregulated in a patU3 mutant. When mutants hetZ::C.K2 and hetZ::Tn5-1087b were nitrogen-deprived, P-hetC-gfp was very weakly expressed, and in hetZ::Tn5-1087b, P-hetR-gfp was relatively strongly expressed in cells that had neither a regular pattern nor altered morphology. We conclude that the hetZ-patU5-patU3 cluster plays an important role in co-ordination of heterocyst differentiation and pattern formation. The presence of homologous clusters in filamentous genera without heterocysts is suggestive of a more general role.