Identification and inactivation of three group 2 sigma factor genes in Anabaena sp. strain PCC 7120.

ABSTRACT: Three new Anabaena sp. strain PCC 7120 genes encoding group 2 alternative sigma factors have been cloned and characterized. Insertional inactivation of sigD, sigE, and sigF genes did not affect growth on nitrate under standard laboratory conditions but did transiently impair the abilities of sigD and sigE mutant strains to establish diazotrophic growth. A sigD sigE double mutant, though proficient in growth on nitrate and still able to differentiate into distinct proheterocysts, was unable to grow diazotrophically due to extensive fragmentation of filaments upon nitrogen deprivation. This double mutant could be complemented by wild-type copies of sigD or sigE, indicating some degree of functional redundancy that can partially mask phenotypes of single gene mutants. However, the sigE gene w

SUBMITTER: Khudyakov IY 

PROVIDER: S-EPMC95499 | biostudies-literature | 2001 Nov

REPOSITORIES: biostudies-literature