title: A Myxococcus xanthus cell density-sensing system required for multicellular development.
abstract: Progression through early Myxococcus xanthus multicellular fruiting body development requires the generation of and response to extracellular A signal. Extracellular A signal is a specific set of amino acids at an extracellular concentration greater than 10 muM. It functions as a cell density signal during starvation that allows the cells to sense that a minimal cell density has been reached and development can proceed. The generation of extracellular A signal requires the products of three asg genes. They have recently been identified as AsgA, a fused two-component histidine protein kinase and response regulator; AsgB, a putative DNA-binding protein; and AsgC, the M, xanthus major sigma factor. Other elements of the A signaling pathway map to the sasB locus and appear to be A signal transducers. These elements are regulators of the earliest A signal-dependent gene, whose promoter is a member of the sigma-54 family. Continued study of the A signaling pathway is expected to identify additional components of this network required for the complex behavioural response of fruiting body formation.
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston 77030, USA.
authors.forename: H B
authors.initials: HB
authors.lastname: Kaplan
authors.forename: L
authors.initials: L
authors.lastname: Plamann
mesh_terms: D002452:Cell Count; D016941:Myxococcus xanthus / Q000166:cytology* / Q000235:genetics / Q000254:growth & development*; D015398:Signal Transduction / Q000235:genetics