dictyNews Volume 40 Number 18

Published in

· 11 months ago

dictyNews 
Electronic Edition 
Volume 40, number 18 
Jul 31, 2014 

Please submit abstracts of your papers as soon as they have been 
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========= 
Abstracts 
========= 

Cross-species Functional Complementation of Cellulose Synthase  
during the development of Cellular Slime Molds 

Hidekazu Kuwayama, Takeru Tohyama, Hideko Urushihara 
Faculty of Life and Environmental Sciences, University of  
Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan 

Development, Growth & Differentiation, in press 

Cellulose is a major and important component of the extracellular  
matrix during the development of Dictyostelium discoideum. Upon  
starvation, solitary amoebae of D. discoideum gather and form  
fruiting bodies in which cells differentiate into stalk cells  
and spores. The stalk tubes and walls of spores and stalk cells  
are made of cellulose. In the genus Acytostelium, however, all  
cells are destined to become spores and the stalks comprise only  
a cellulose tube, suggesting species-specific regulation of  
cellulose synthesis. In this study, we cloned a putative cellulose  
synthase gene (cesA) of Acytostelium subglobosum and performed  
comparative analyses with the D. discoideum cellulose synthase  
gene (dcsA). Although the deduced amino acid sequences were  
highly conserved between cesA and dcsA, the numbers of  
transmembrane spans preceding the catalytic domain were  
dissimilar; 2 and 3, respectively. Since ectopic expression  
of cesA in dcsA-null cells failed to restore the developmental  
defects of the mutant, we constructed a series of chimerical  
genes for complementation analyses and found that the catalytic  
domain of cesA was functional in D. discoideum cells if the  
preceding transmembrane region was swapped with dcsA. The  
non-functional products that contained the cesA-derived  
transmembrane region were localized to lysosomes. These results  
indicate that the transmembrane region of cellulose synthase is  
essential for proper accumulation of cellulose during the  
development of D. discoideum and that its differential  
localization in A. subglobosum may be related to the  
characteristic morphogenesis in this species. 

Submitted by Hidekazu Kuwayama [hidekuwayama@biol.tsukuba.ac.jp] 
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[End dictyNews, volume 40, number 18]