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dictyNews Volume 41 Number 15
dictyNews
Electronic Edition
Volume 41, number 15
July 18, 2015
Please submit abstracts of your papers as soon as they have been
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Abstracts
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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]
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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]
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[End dictyNews, volume 41, number 15]
