dictyNews Electronic Edition Volume 41, number 15 July 18, 2015 Please submit abstracts of your papers as soon as they have been accepted for publication by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Back issues of dictyNews, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. Follow dictyBase on twitter: http://twitter.com/dictybase ========= Abstracts ========= Absence of catalytic domain in a putative protein kinase C (PkcA) suppresses tip dominance in Dictyostelium discoideum Wasima Mohamed a, Sibnath Ray b, Derrick Brazill b, Ramamurthy Baskar a, a Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India b Department of Biological Sciences, Center for Translational and Basic Research, Hunter College and The Graduate Center of the City University of New York, New York, NY 10065 Developmental Biology, in press A number of organisms possess several isoforms of protein kinase C but little is known about the significance of any specific isoform during embryogenesis and development. To address this we characterized a PKC ortholog (PkcA; DDB_G0288147) in Dictyostelium discoideum. pkcA expression switches from prestalk in mound to prespore in slug, indicating a dynamic expression pattern. Mutants lacking the catalytic domain of PkcA (pkcA-) did not exhibit tip dominance. A striking phenotype of pkcA- was the formation of an aggregate with a central hollow, and aggregates later fragmented to form small mounds, each becoming a fruiting body. Optical density wave patterns of cAMP in the late aggregates showed several cAMP wave generation centers. We attribute these defects in pkcA- to impaired cAMP signaling, altered cell motility and decreased expression of the cell adhesion molecules- CadA and CsaA. pkcA- slugs showed ectopic expression of ecmA in the prespore region. Further, the use of a PKC-specific inhibitor, GF109203X that inhibits the activity of catalytic domain phenocopied pkcA-. Submitted by Ramamurthy Baskar [rbaskar@IITM.AC.IN] ---------------------------------------------------------------------- The GATA transcription factor GtaC regulates early developmental gene expression dynamics in Dictyostelium Balaji Santhanam1,2,4, Huaqing Cai3, Peter N. Devreotes3, Gad Shaulsky2,5 and Mariko Katoh-Kurasawa2,4,5 1 Graduate Program in Structural Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030 2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 3 Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205 4 These authors contributed equally to this work. 5 Corresponding authors Nature Communications, Article number:7551| doi:10.1038/ncomms8551 In many systems, including the social amoeba Dictyostelium discoideum, development is often marked by dynamic morphological and transcriptional changes orchestrated by key transcription factors. However, efforts to examine sequential genome-wide changes of gene regulation in developmental processes have been fairly limited. Here we report the developmental regulatory dynamics of GtaC, a GATA-type zinc-finger transcription factor, through the analyses of serial ChIP- and RNA-sequencing data. GtaC is essential for developmental progression, decoding extracellular cAMP pulses during early development and may play a role in mediating cell-type differentiation at later stages. We find that GtaC exhibits temporally distinctive DNA-binding patterns concordant with each developmental stage. We identify direct GtaC targets and observe cotemporaneous GtaC-binding and developmental expression regulation. Our results suggest that GtaC regulates multiple physiological processes as Dictyostelium transitions from a group of unicellular amoebae to an integrated multicellular organism. Submitted by Mariko Katoh-Kurasawa[mkatoh@bcm.edu] ============================================================== [End dictyNews, volume 41, number 15]