Open AccessCharacterization of devH , a Gene Encoding a Putative DNA Binding Protein Required for Heterocyst Function in Anabaena sp. Strain PCC 7120
Author(s) -
Pratibha B. Hebbar,
S. E. Curtis
Publication year - 2000
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.182.12.3572-3581.2000
Subject(s) - biology , mutant , heterocyst , anabaena , gene , open reading frame , plasmid , gene product , dna , genetics , promoter , microbiology and biotechnology , activator (genetics) , gene expression , peptide sequence , cyanobacteria , bacteria
ThedevH gene was identified in a screen forAnabaena sp. strain PCC 7120 sequences whose transcripts increase in abundance during a heterocyst development time course. The product ofdevH contains a helix-turn-helix motif similar to the DNA binding domain of members of the cyclic AMP receptor protein family, and the protein is most closely related to the cyanobacterial transcriptional activator NtcA.devH transcripts are barely detectable in vegetative cells and are induced approximately fivefold after nitrogen starvation. This induction is absent in the two developmental mutantshetR andntcA . The gene is expressed as monocistronic transcripts with multiple 5′ termini, and the ∼500-bp region 5′ todevH was shown to have promoter activity in vivo. ThedevH gene was insertionally inactivated by the integration of plasmid sequences within the open reading frame. Nitrogen starvation of thedevH mutant induces heterocysts of wild-type morphology, but the mutant is inviable in the absence of fixed nitrogen and unable to reduce acetylene aerobically.