During fruiting body formation in myxococcus xanthus, dramatic changes occur in gene expression. We plan to analyze several developmentally regulated genes in order to learn how these changes are regulated. 1) The mbhA gene encodes a lectin which appears during aggregation. The promoter for this gene resembles the nitrogen regulated promoters from E. coli. We plan to use site-directed mutagenesis to characterize this promoter. We also plan to locate the upstream enhancer sequences, previously identified, and search for proteins which recognize it. We will use the Salmonella ntrA gene to clone and sequence the Myxococcus NTRA-like sigma factor. We also plan to examine why the mbhA mRNA has such a long half-life, 2 hrs. 2) frz genes are homologous to Salmonella chemotaxis gene. They are developmentally induced, but not an operon. The role of frzCD in stimulating the other frz genes will be studied since it contains a DNA-binding domain similar to sigma-43. Missense mutations in this domain will be isolated. Fusion proteins will be purified and assayed for DNA-binding activity. We will also identify the transcripts and promoters of the frz genes. 3) Alkaline phosphatase is induced at late times of development (sporulation). We will clone and sequence the gene. The cloned gene will be used to study late gene expression.
