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Systematic analysis of the Myxococcus xanthus developmental gene regulatory network supports posttranslational regulation of FruA by C‐signaling
Author(s) -
Saha Shreya,
Patra Pintu,
Igoshin Oleg,
Kroos Lee
Publication year - 2019
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14249
Subject(s) - myxococcus xanthus , biology , mutant , transcription factor , microbiology and biotechnology , signal transduction , operon , genetics , gene , multicellular organism , transcription (linguistics) , linguistics , philosophy
Summary Upon starvation Myxococcus xanthus undergoes multicellular development. Rod‐shaped cells move into mounds in which some cells differentiate into spores. Cells begin committing to sporulation at 24–30 h poststarvation, but the mechanisms governing commitment are unknown. FruA and MrpC are transcription factors that are necessary for commitment. They bind cooperatively to promoter regions and activate developmental gene transcription, including that of the dev operon. Leading up to and during the commitment period, dev mRNA increased in wild type, but not in a mutant defective in C‐signaling, a short‐range signaling interaction between cells that is also necessary for commitment. The C‐signaling mutant exhibited ~20‐fold less dev mRNA than wild type at 30 h poststarvation, despite a similar level of MrpC and only 2‐fold less FruA. Boosting the FruA level twofold in the C‐signaling mutant had little effect on the dev mRNA level, and dev mRNA was not less stable in the C‐signaling mutant. Neither did high cooperativity of MrpC and FruA binding upstream of the dev promoter explain the data. Rather, our systematic experimental and computational analyses support a model in which C‐signaling activates FruA at least ninefold posttranslationally in order to commit a cell to spore formation.