dictyNews Volume 28 Number 01

Published in

· 1 year ago

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

Please submit abstracts of your papers as soon as they have been 
accepted for publication by sending them to dicty@northwestern.edu 
or 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. 

 
========= 
  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]