Genetic studies of mrp, a locus essential for cellular aggregation and sporulation of Myxococcus xanthus
Genetic studies of mrp, a locus essential for cellular aggregation and sporulation of Myxococcus xanthus
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DOI：
10.1128/jb.183.16.4786-4795.2001
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发表时间：
2001-08-01
影响因子：
3.2
通讯作者：
Shi, WY
中科院分区：
文献类型：
--
作者：
Sun, H;Shi, WY
在饥饿条件下，黄色粘球菌经历了一个复杂的发育过程，包括细胞聚集和孢子形成。在这项研究中，转座子插入突变体（Tn 5-欧姆280突变体）的缺陷，在聚集和孢子形成进行了分析。发现Tn 5-Ohm 280突变体具有被破坏的NtrC样应答调节物，其被命名为粘球菌调节蛋白B（mrp B）。进一步的测序分析显示，一个组氨酸激酶同源物（mrpA）的mrpB和环AMP受体蛋白样转录调节因子（mrpC）的mrpB下游的上游。框内缺失分析表明，mrpB和mrpC基因都需要细胞聚集和孢子形成，但只有mrpA是所需的孢子形成。MrpB，D58的假定磷酸化位点的位点特异性诱变表明，D58 A突变导致聚集和孢子形成缺陷，但D58 E突变仅导致孢子形成缺陷。报告基因和逆转录-PCR的进一步遗传和分子分析表明，mrpA和mrpB是共转录的，但mrpC是独立转录的，所有这些基因的发育调控。此外，MrpB对mrpC的转录至关重要，而MrpC调节其自身的转录。这些数据表明Mrp蛋白是M. xanthus发育Mrp蛋白之间复杂的相互作用可能在调控M. xanthus
Under starvation conditions, Myxococcus xanthus undergoes a complex developmental process which includes cellular aggregation and sporulation. A transposon insertion mutant (the Tn5-Ohm 280 mutant) with defects in both aggregation and sporulation was analyzed in this study. The Tn5-Ohm 280 mutant was found to have a disrupted NtrC-like response regulator designated Myxococcus regulatory protein B (mrpB). Further sequencing analyses revealed a histidine kinase homolog (mrpA) immediately upstream of mrpB and a cyclic AMP receptor protein-like transcriptional regulator (mrpC) downstream of mrpB. In-frame deletion analyses revealed that both the mrpB and mrpC genes were required for cellular aggregation and sporulation but that only mrpA was required for sporulation only. Site-specific mutagenesis of the putative phosphorylation site of MrpB, D58, showed that a D58A mutation caused defects in both aggregation and sporulation but that a D58E mutation resulted in only a sporulation defect. Further genetic and molecular analyses with reporter genes and reverse transcription-PCR indicated that mrpA and mrpB are cotranscribed but that mrpC is transcribed independently and that all of these genes are developmentally regulated. In addition, MrpB is essential for transcription of mrpC and MrpC regulates its own transcription. These data indicate that Mrp proteins are important components required for M. xanthus development. The complicated interaction between Mrp proteins may play an important role in regulating developmental gene expression in M. xanthus.