Developmental bypass suppression of Myxococcus xanthus csgA mutations.
AUTOR(ES)
Rhie, H G
RESUMO
The csgA mutations of Myxococcus xanthus (formerly known as spoC) inhibit sporulation as well as rippling, which involves ridges of cells moving in waves. Sporulating revertants of CsgA cells were isolated by direct selection, since spores are much more resistant to heat and ultrasonic treatment than are vegetative cells. The revertants fell into seven groups on the basis of phenotype and the chromosomal location of the suppressor alleles. Group 1 contained one allele that was a back mutation of the original csgA mutation. Group 2 contained two linked alleles that were unlinked to the csgA locus and restored fruiting-body formation, sporulation, and rippling. Group 3 revertants regained the ability to sporulate in fruiting bodies but not the ability to ripple. Revertants in groups 4 to 7 were able to sporulate but unable to form fruiting bodies or ripples. The suppressors were all found to be bypass suppressors even though they were not selected as such in most cases. The csgA mutation prevented expression of several developmentally regulated promoters, each fused to a lacZ reporter gene and assayed by beta-galactosidase production. In four of five suppressor groups (groups 4 to 7), expression of each of these csgA-dependent fusions was restored, which suggests that bypass suppression restores developmental gene expression near the point at which expression is disrupted in CsgA mutants. Bypass suppression did not restore production of C factor, and morphological manifestations of development such as rippling and fruiting-body formation were usually abnormal. One interpretation of these results is that C factor has multiple functions and few suppressors can compensate for all of them.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=210045Documentos Relacionados
- Effect of dsp mutations on the cell-to-cell transmission of CsgA in Myxococcus xanthus.
- Low-temperature induction of Myxococcus xanthus developmental gene expression in wild-type and csgA suppressor cells.
- CsgA, an extracellular protein essential for Myxococcus xanthus development.
- The stringent response in Myxococcus xanthus is regulated by SocE and the CsgA C-signaling protein
- Characterization of bcsA Mutations That Bypass Two Distinct Signaling Requirements for Myxococcus xanthus Development