Overexpression of the response regulator <i>rpaA</i> causes an impaired cell division in the Cyanobacterium <i>Synechocystis</i> sp. PCC 6803
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- Kizawa Ayumi
- Department of Agricultural Chemistry, School of Agriculture, Meiji University
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- Osanai Takashi
- Department of Agricultural Chemistry, School of Agriculture, Meiji University
抄録
<p>In photosynthetic microorganisms, cell cycle progression depends on day and night cycles; however, how cell division is regulated in response to these environmental changes is poorly understood. RpaA has been implicated in the signal output from both circadian clocks and light/dark conditions in the unicellular spherical-celled cyanobacterium Synechocystis sp. PCC 6803. In the present study, we investigated the involvement of a two-component response regulator RpaA in cell division regulation. Firstly, we examined the effects of rpaA overexpression on cell morphology and the expression levels of cell division genes. We observed an increase in the volume of non-dividing cells and a high proportion of dividing cells in rpaA-overexpressing strains by light microscopy. The expression levels of selected cell division-related genes were higher in the rpaA-overexpressing strain than in the wild type, including minD of the Min system; cdv3 and zipN, which encode two divisome components; and murB, murC, and pbp2, which are involved in peptidoglycan (PG) synthesis. Moreover, in the rpaA-overexpressing strain, the outer membrane and cell wall PG layer were not smooth, and the outer membrane was not clearly visible by transmission electron microscopy. These results demonstrated that rpaA overexpression causes an impaired cell division, which is accompanied by transcriptional activation of cell division genes and morphological changes in the PG layer and outer membrane.</p>
収録刊行物
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- The Journal of General and Applied Microbiology
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The Journal of General and Applied Microbiology 66 (2), 121-128, 2020
公益財団法人 応用微生物学・分子細胞生物学研究奨励会
