Identification and characterization of FrzZ, a novel response regulator necessary for swarming and fruiting-body formation in Myxococcus xanthus.
The frz genes of Myxococcus xanthus constitute a signal-transduction pathway that processes chemotactic information in a manner analogous to that found in enteric bacteria. Ultimately, these genes regulate the frequency of individual cell reversal. We report here the identification of a novel component of this signal-transduction pathway, designated frzZ, which was discovered as an open reading frame located 5' to the frz operon but transcribed in the opposite orientation. The translational start site of frzZ is 170 base pairs from that of frzA.frzZ utilizes a promoter similar to the sigma 70 promoters of Escherichia coli, and encodes a 290-amino-acid soluble protein, FrzZ (M(r) 30,500). FrzZ contains two domains, both of which show strong homology to CheY and other members of the response-regulator family. Linking these domains is a 39-amino-acid region that is very rich in alanine and proline (38% Ala and 33% Pro). A frzZ null mutant showed abnormally low reversal rates when compared to the wild-type control and was unable to form fruiting bodies on starvation medium, but it did form 'frizzy' aggregates. In addition, the frzZ mutant was defective in swarming, particularly on soft agar (0.3% w/v). However, unlike most frz mutants, the frzZ mutant was able to respond to attractants and repellents in the spatial chemotaxis assay. The discovery of FrzZ demonstrates that the M. xanthus frz signal-transduction pathway utilizes multiple response-regulator (CheY-like) proteins.
Trudeau
K G
KG
Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA.
Ward
M J
MJ
Zusman
D R
DR
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002633:Chemotaxis; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D000072236:Methyl-Accepting Chemotaxis Proteins; D008969:Molecular Sequence Data; D016941:Myxococcus xanthus / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C103380:FrzZ protein, Myxococcus xanthus; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C000607606:cheY protein, E coli