Role of the all1549 (ana-rsh) Gene, A relA/spoT Homolog, of the Cyanobacterium Anabaena sp. PCC7120
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- Ning, D., Qian, Y., Miao, X. et al. Curr Microbiol (2011) 62: 1767. doi:10.1007/s00284-011-9926-0
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The role of a single relA/spoT homolog all1549 (designated hereafter as ana-rsh) of the cyanobacterium Anabaena sp. PCC7120 was investigated. The complementation test in Escherichiacoli showed that the protein encoded by ana-rsh possesses guanosine tetraphosphate (p)ppGpp-synthase/hydrolase activity. Under laboratory growth conditions, a low level of ppGpp was detected in Anabaena sp. PCC7120 and the loss of ana-rsh was lethal. Amino acid starvation induced ppGpp accumulation to an appropriate level, and nitrogen deficiency did not alter the ppGpp concentration in Anabaena cells. These data suggest that ana-rsh is required for cell viability under normal growth conditions and involved in the (p)ppGpp-related stringent response to amino acid deprivation, but not related to heterocyst formation and nitrogen fixation of Anabaena sp. PCC7120.