title: devRS, an autoregulated and essential genetic locus for fruiting body development in Myxococcus xanthus.
abstract: Two Tn5 lac insertions into the Myxococcus genome at sites omega 4414 and omega 4473, which are separated by 550 nucleotides, inactivate fruiting body development. Sporulation is decreased 100- to 10,000-fold. At least two genes, devR and devS, are transcribed in this region, probably as an operon. Expression of devR begins by 6 h after starvation has initiated development. On the basis of their nucleotide sequences, devR and devS are expected to encode proteins of 302 and 214 amino acids, respectively. Dev+ function can be restored by a segment of 7.8 kb cloned from the devRS region of wild-type cells. Two experiments show that devR expression is under strong negative autoregulation. beta-Galactosidase is expressed at a higher level from a transcriptional devR::lacZ fusion when the fused operon is in a dev strain than when it is in the dev/dev+ genetic background of a partial diploid. There is more mRNA accumulation from the devRS region in the dev strain than in a rescued dev/dev+ tandem duplication strain. Sporulation rescue is correlated with some degree of negative autoregulation, even though sporulation is not inversely proportional to beta-galactosidase expression from omega 4414. A second level of regulation is suggested by complementation of dev by dev+ in duplication strains. The expression of devRS, measured by sporulation levels, differs 1,000-fold when devRS+ is moved from a distance of 20 kb to 3 Mb from the mutant devRS locus. Expression of devR is also dependent on the cell density at which development is initiated, a third level of regulation. Multiple levels of regulation suggest that devRS is a switch required to activate completion of aggregation and sporulation.
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, California 94305-5427.
authors.forename: L
authors.initials: L
authors.lastname: Thöny-Meyer
authors.forename: D
authors.initials: D
authors.lastname: Kaiser
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000302:isolation & purification / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D007700:Kinetics; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016941:Myxococcus xanthus / Q000235:genetics* / Q000254:growth & development* / Q000502:physiology; D016366:Open Reading Frames; D010957:Plasmids; D012329:RNA, Bacterial / Q000302:isolation & purification / Q000378:metabolism; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism; D013171:Spores, Bacterial / Q000502:physiology; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012333:RNA, Messenger; D001616:beta-Galactosidase