dictyNews
Electronic Edition
Volume 28, number 1
January 12, 2007

Please submit abstracts of your papers as soon as they have been
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http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit.

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=========
  Abstracts
=========



Pharmacological evidence that stalk cell differentiation involves increases in 
the intracellular Ca2+and H+ concentrations in Dictyostelium discoideum.

Yuzuru Kubohara*, Akiko Arai, Naomi Gokan, Kohei Hosaka

*Department of Molecular and Cellular Biology, Institute for Molecular and 
Cellular Regulation (IMCR), Gunma University, Maebashi 371-8512, Japan


Develop. Growth & Differ, in press.

Differentiation-inducing factors (DIFs) are required for stalk cell formation in 
Dictyostelium discoideum.  In the present study, in order to support our 
hypothesis that DIFs may function via increases in [Ca2+]c and [H+]c, we 
investigated the combined effects of 5,5-dimethyl-2,4-oxazolidinedione 
(DMO: a [H+]c-increasing agent), thapsigargin (Tg), and 
BHQ ([Ca2+]c-increasing agents) on in vitro stalk cell formation in several 
strains.  DMO, in combination with Tg or BHQ, induced stalk cell formation 
in a DIF-deficient mutant HM44.  Although the rates of stalk cell induction 
by the drugs were low in the presence of cerulenin (an inhibitor of 
endogenous DIF production) in HM44 and V12M2 (a wild-type strain), the 
drugs succeeded in inducing sufficient stalk cell formation when a small 
amount of DIF-1 was supplied.  Furthermore, co-addition of DMO, BHQ, and 
a small amount of DIF-1also induced sufficient stalk cell formation in AX-4 
(an axenic strain) and HM1030 (dmtA-) but not in CT15 (dimA-).  The drugs 
suppressed spore formation and promoted stalk cell formation in both HM18 
(a sporogenous mutant) and 8-bromo-cAMP-stimulated V12M2.  The 
present results suggest that DIFs function, at least in part, via increases in 
[Ca2+]c and [H+]c in D. discoideum.


Submitted by Yuzuru Kubohara [kubohara@showa.gunma-u.ac.jp]
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[End dictyNews, volume 28, number 1]