title: Reverse genetic analyses of gamete-enriched genes revealed a novel regulator of the cAMP signaling pathway in Dictyostelium discoideum.
abstract: Sexual development in Dictyostelium discoideum is initiated by the fusion of opposite mating type cells to form zygote giant cells, which subsequently gather and phagocytose surrounding cells for nutrition to form macrocysts. Here we performed the targeting of 24 highly gamete-enriched genes we previously isolated, and successfully generated knockout mutants for 16 genes and RNAi mutants for 20 genes including 6 genes without disruptants. In the knockout mutants of two genes, cell aggregation toward the giant cells was much less extensive and many cells remained around poorly formed macrocysts. We named these genes tmcB and tmcC. Although macrocyst formation of wild type cells was suppressed by the addition of exogenous cAMP, that of knockout mutants of tmcB was much less sensitive. The mRNA level of phosphodiesterase (pde) was higher and that of its inhibitor (pdi) was lower in the latter cells compared to the parental strains during sexual development. Thus, tmcB appeared to be a novel regulator of the cAMP signaling pathway specific to sexual development. Knockout mutants of tmcC were indistinguishable from the wild type cells with respect to the cAMP response, suggesting that this gene is relevant to other processes.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba-shi 305-8572, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Muramoto
authors.forename: Shugaku
authors.initials: S
authors.lastname: Takeda
authors.forename: Yoko
authors.initials: Y
authors.lastname: Furuya
authors.forename: Hideko
authors.initials: H
authors.lastname: Urushihara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D000242:Cyclic AMP / Q000378:metabolism*; D004023:Dictyostelium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005821:Genetic Techniques; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000502:physiology; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D012313:RNA / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D012313:RNA; D000242:Cyclic AMP