dictyNews Volume 27 Number 17

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dictyNews 
Electronic Edition 
Volume 27, number 17 
December 22, 2006 

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 
========= 

 

cAMP production by adenylyl cyclase G  induces prespore differentiation  
in Dictyostelium slugs 

Elisa Alvarez-Curto, Shweta Saran, Marcel Meima, Jenny Zobel, Claire  
Scott and Pauline Schaap* 

Division of Cell and Developmental Biology, College of Life Sciences,  
University of Dundee, Dundee, Angus DD1 5EH, UK 

 
Development, in press 

Encystation and sporulation are crucial developmental transitions for  
solitary and social amoebas, respectively. While little is known of  
encystation, sporulation requires both extra- and intracellular cAMP.  
After aggregation of social amoebas, extracellular cAMP binding to surface  
receptors and intracellular cAMP binding to cAMP dependent protein kinase  
(PKA) act together to induce prespore differentiation. Later, a second  
episode of PKA activation triggers spore maturation. Adenylyl cyclase B  
(ACB) produces cAMP for maturation, but the cAMP source for prespore  
induction is unknown. We show that adenylyl cyclase G (ACG) protein is  
upregulated in prespore tissue after aggregation. acg null mutants show  
reduced prespore differentiation, which becomes very severe when ACB is  
also deleted. ACB is normally expressed in prestalk cells, but is  
upregulated in the prespore region of acg null structures. These data  
show that ACG induces prespore differentiation in wild-type cells, with  
ACB capable of partially taking over this function in  its absence.  

 
Submitted by Pauline Schaap [p.schaap@dundee.ac.uk] 
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Treasure hunt in an amoeba: non-coding RNAs in Dictyostelium discoideum 

Andrea Hinas and Fredrik Soderbom 

Department of Molecular Biology, Biomedical Center, Swedish University  
of Agricultural Sciences, Box 590, 75124 Uppsala, Sweden 

 
Current Genetics, in press 
Review Article 

Abstract  The traditional view of RNA being merely an intermediate in the  
transfer of genetic information, as mRNA, spliceosomal RNA, tRNA, and  
rRNA, has become outdated. The recent discovery of numerous regulatory  
RNAs with a plethora of functions in biological processes has truly  
revolutionized our understanding of gene regulation. Tiny RNAs such as  
microRNAs and small interfering RNAs play vital roles at different levels of  
gene control. Small nucleolar RNAs are much more abundant than  
previously recognized, and new functions beyond processing and  
modification of rRNA have recently emerged. Longer non-coding RNAs  
(ncRNAs) can also have important regulatory roles in the cell, e.g.,  
antisense RNAs that control their target mRNAs. The majority of these i 
mportant findings arose from analyses in various model organisms. In this  
review, we focus on ncRNAs in the social amoeba Dictyostelium  
discoideum. This important genetically tractable model organism has  
recently received renewed attention in terms of discovery, regulation and  
functional studies of ncRNAs. Old and recent findings are discussed and  
put in context of what we today know about ncRNAs in other organisms. 

 
Submitted by: Fredrik Soderbom [fredde@xray.bmc.uu.se] 
-------------------------------------------------------------------------------- 

 
Dictyostelium Myb transcription factors function at culmination as activators  
of ancillary stalk differentiation 

Masatsune Tsujioka*, Natasha Zhukovskaya*, Yoko Yamada, Masashi  
Fukuzawa, Susan Ross and Jeffrey G. Williams 
*contributed equally 

University of Dundee 
MSI/WTB Complex 
Dow Street 
Dundee DD1 5EH 
UK 

Eukaryotic Cell in press 

ecmB and mrrA are expressed in the cups that cradle Dictyostelium  
spore-heads and MybE is necessary for their expression in lower but not  
upper cup cells. A Myb site within the mrrA promoter is necessary for  
expression in both cups. Thus multiple Myb proteins are required for  
ancillary stalk differentiation. 

 
Submitted by: Jeff Williams [j.g.williams@dundee.ac.uk] 
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[End dictyNews, volume 27, number 17]