Selection of unusual actinomycetal primary sigma70 factors by plant-colonizing Frankia strains.

ABSTRACT: Functional adaptations of sigma70 transcriptional factors led to the emergence of several paralogous lineages, each one being specialized for gene transcription under particular growth conditions. Screening of a Frankia strain EaI-12 gene library by sigma70 DNA probing allowed the detection and characterization of a novel actinomycetal primary (housekeeping) sigma70 factor. Phylogenetic analysis positioned this factor in the RpoD cluster of proteobacterial and low-G+C-content gram-positive factors, a cluster previously free of any actinobacterial sequences. sigma70 DNA probing of Frankia total DNA blots and PCR screening detected one or two rpoD-like DNA regions per species. rpoD matched the conserved region in all of the species tested. The other region was found to contain sigA, an alter

SUBMITTER: Lavire C 

PROVIDER: S-EPMC348808 | biostudies-literature | 2004 Feb

REPOSITORIES: biostudies-literature