Abstract
Two genes, fruA and csgA, encoding a putative transcription factor and C-factor, respectively, are essential for fruiting body formation of Myxococcus xanthus. To investigate the role of fruA and csgA genes in developmental gene expression, developing cells as well as vegetative cells of M. xanthus wild-type, fruA::Tc, and csgA731 strains were pulse-labeled with [(35)S]methionine, and the whole cell proteins were analyzed using two-dimensional immobilized pH gradient/SDS-PAGE. Differences in protein synthesis patterns among more than 700 protein spots were detected during development of the three strains. Fourteen proteins showing distinctly different expression patterns in mutant cells were analyzed in more detail. Five of the 14 proteins were identified as elongation factor Tu (EF-Tu), Dru, DofA, FruA, and protein S by immunoblot analysis and mass spectroscopy. A gene encoding DofA was cloned and sequenced. Although both fruA and csgA genes regulate early development of M. xanthus, they were found to differently regulate expression of several developmental genes. The production of six proteins, including DofA and protein S, was dependent on fruA, whereas the production of two proteins was dependent on csgA, and one protein was dependent on both fruA and csgA. To explain the present findings, a new model was presented in which different levels of FruA phosphorylation may distinctively regulate the expression of two groups of developmental genes.
Highlights
Two genes, fruA and csgA, encoding a putative transcription factor and C-factor, respectively, are essential for fruiting body formation of Myxococcus xanthus
Protein spots were profiled and quantified using Melanie II 2-D PAGE software. Both of the two-dimensional gel electrophoresis (GE) images contained 700 –1200 distinct protein spots depending on the gel exposure time to x-ray film and the amount of proteins applied to the gels
The patterns of protein synthesis during vegetative growth and development of M. xanthus have been analyzed by two-dimensional GE
Summary
The fruA mutant exhibited a phenotype similar to that of the csgA mutant [19, 21]. A model in which C-signal transduction requires FruA function was proposed [20, 21]. To investigate the effects of csgA and fruA mutations on developmental gene expression in M. xanthus, developing cells as well as vegetative cells were pulse-labeled with [35S]methionine, and whole cell proteins were analyzed using two-dimensional immobilized pH gradient/sodium dodecyl sulfate-polyacrylamide gel electrophoresis (GE), which has been used to analyze heat-shock-induced proteins in M. xanthus [22]. At least 14 proteins exhibited apparently different expression patterns among the wild-type, fruA::Tc, and csgA731 strains during development. We succeeded in cloning a novel gene, dofA, whose expression was dependent on FruA function. These proteins are useful as developmental markers for the analysis of M. xanthus fruiting body formation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
