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alr0117, a two-component histidine kinase gene, is involved in heterocyst development in Anabaena sp. PCC 7120

2004; Microbiology Society; Volume: 150; Issue: 2 Linguagem: Inglês

10.1099/mic.0.26747-0

1465-2080

Degang Ning, Xudong Xu,

Bacterial Genetics and Biotechnology

Anabaena sp. PCC 7120 was mutagenized by transposon Tn 5 -1087b, generating a mutant whose heterocysts lack the envelope polysaccharide layer. The transposon was located between nucleotides 342 and 343 of alr0117 , a 918 bp gene encoding a histidine kinase for a two-component regulatory system. Complementation of the mutant with a DNA fragment containing alr0117 and targeted inactivation of the gene confirmed that alr0117 is involved in heterocyst development. RT-PCR showed that alr0117 was constitutively expressed in the presence or absence of a combined-nitrogen source. hepA and patB , the two genes turned on during wild-type heterocyst development, were no longer activated in an alr0117 -null mutant. The two-component signal transduction system involving alr0117 may control the formation of the envelope polysaccharide layer and certain late events essential to the function of heterocysts.