HetF and PatA Control Levels of HetR in Anabaena sp. Strain PCC 7120

dc.contributor.author Risser, Douglas D.
dc.contributor.author Callahan, Sean M.
dc.date.accessioned 2016-05-05T02:51:18Z
dc.date.available 2016-05-05T02:51:18Z
dc.date.issued 2008-10
dc.description.abstract Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that differentiates heterocysts in response to deprivation of combined nitrogen. A hetF deletion strain lacked heterocysts and had aberrant cell morphology. Site-directed mutagenesis of the predicted active-site histidine and cysteine residues of this putative caspasehemoglobinase fold protease abolished HetF function, supporting the hypothesis that HetF is a protease. Deletion of patA, which is necessary for the formation of most intercalary heterocysts, or hetF resulted in an increase in HetR protein, and extra copies of hetF on a plasmid functionally bypassed the deletion of patA. A hetR-gfp translational fusion expressed from an inducible promoter demonstrated that hetF-dependent downregulation of HetR levels occurs rapidly in vegetative cells, as well as developing heterocysts. “Mosaic” filaments in which only one cell of a filament had a copy of hetR or hetF indicated that hetF is required for differentiation only in cells that will become heterocysts. hetF was required for transcription from a hetRdependent transcription start point of the hetR promoter and induction of transcription from the patS promoter. The inverse correlation between the level of HetR protein and transcription from hetR-dependent promoters suggests that the transcriptional activity of HetR is regulated by HetF and PatA.
dc.format.extent 10
dc.identifier.doi 10.1128/JB.01110-08
dc.identifier.uri http://hdl.handle.net/10125/40615
dc.language.iso en-US
dc.publisher American Society for Microbiology
dc.relation.uri http://jb.asm.org/content/190/23/7645.long
dc.rights Copyright © 2008, American Society for Microbiology. All Rights Reserved.
dc.title HetF and PatA Control Levels of HetR in Anabaena sp. Strain PCC 7120
dc.type Article
dc.type.dcmi Text
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