PMID:11359579

Citation	Gronewold, TM and Kaiser, D (2001) The act operon controls the level and time of C-signal production for Myxococcus xanthus development. Mol. Microbiol. 40:744-56
Abstract	The C-signal is a morphogen that controls the assembly of fruiting bodies and the differentiation of myxospores. Production of this signal, which is encoded by the csgA gene, is regulated by the act operon of four genes that are co-transcribed from the same start site. The act A and act B genes regulate the maximum level of the C-signal, which never rises above one-quarter of the maximum wild-type level of CsgA protein in null mutants of either gene. The act A and act B mutants have the same developmental phenotype: both aggregate, neither sporulates, both prolong rippling. By sequence homology, act A encodes a response regulator, and act B encodes a sigma-54 activator protein of the NTRC class. The similar phenotypes of act A and act B deletion mutants suggest that the two gene products are part of the same signal transduction pathway. That pathway responds to C-signal and also regulates the production of CsgA protein, thus creating a positive feedback loop. The act C and act D genes regulate the time pattern of CsgA production, while achieving the same maximum level. An act C null mutant raises CsgA production 15 h earlier than the wild type, whereas an act D null mutant does so 6 h later than wild type. The loop explains how the C-signal rises continuously from early development to a peak at the time of sporulation, and the act genes govern the time course of that rise.
Links	PubMed
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Bacterial Proteins/physiology; Base Sequence; DNA, Bacterial; Gene Expression Regulation, Bacterial; Membrane Proteins/genetics; Membrane Proteins/physiology; Molecular Sequence Data; Myxococcus xanthus/genetics; Myxococcus xanthus/growth & development; Myxococcus xanthus/metabolism; Myxococcus xanthus/physiology; Operon/physiology; RNA, Messenger; Signal Transduction; Time Factors
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
MYXXA:Q93P59	involved_in	GO:0009966: regulation of signal transduction	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
MYXXA:Q93P59	involved_in	GO:0043937: regulation of sporulation	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
MYXXA:Q93P59		GO:0030583: fruiting body development in cellular response to starvation	ECO:0000315:		P		Figure 5, Table 1	complete CACAO 2714
MYXXA:Q93P59		GO:0009966: regulation of signal transduction	ECO:0000315:		P		Figure 6	complete CACAO 2715
MYXXA:Q93P59		GO:0043937: regulation of sporulation	ECO:0000315:		P		Table 2	complete CACAO 2724
MYXXD:Q1D7F8	involved_in	GO:0043937: regulation of sporulation	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
MYXXD:Q1D7F8	involved_in	GO:0042594: response to starvation	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
MYXXD:Q1D7F8		GO:0009966: regulation of signal transduction	ECO:0000315:		P		Figures 6 and 7	complete CACAO 2716
MYXXD:Q1D7F8		GO:0042594: response to starvation	ECO:0000315:		P		Figure 5, Table 1	complete CACAO 2717
MYXXD:Q1D7F8		GO:0043937: regulation of sporulation	ECO:0000315:		P		Table 2	complete CACAO 2723
MYXXA:Q93P57	involved_in	GO:0009966: regulation of signal transduction	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
MYXXA:Q93P57		GO:0031155: regulation of fruiting body development	ECO:0000315:		P		Figure 5	complete CACAO 2720
MYXXA:Q93P57		GO:0009966: regulation of signal transduction	ECO:0000315:		P		Figure 6	complete CACAO 2721
MYXXA:Q93P57		GO:0043937: regulation of sporulation	ECO:0000315:		P		Table 2	complete CACAO 2722
MYXXA:Q93P57	involved_in	GO:0031155: regulation of reproductive fruiting body development	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
MYXXA:Q93P57	involved_in	GO:0043937: regulation of sporulation	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

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