Document Detail


Aspergillus fumigatus RasA regulates asexual development and cell wall integrity.
MedLine Citation:
PMID:  18606827     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The Ras family of proteins is a large group of monomeric GTPases. Members of the fungal Ras family act as molecular switches that transduce signals from the outside of the cell to signaling cascades inside the cell. A. fumigatus RasA is 94% identical to the essential RasA gene of Aspergillus nidulans and is the Ras family member sharing the highest identity to Ras homologs studied in many other fungi. In this study, we report that rasA is not essential in A. fumigatus, but its absence is associated with slowed germination and a severe defect in radial growth. The DeltarasA hyphae were more than two times the diameter of wild-type hyphae, and they displayed repeated changes in the axis of polarity during hyphal growth. The deformed hyphae accumulated numerous nuclei within each hyphal compartment. The DeltarasA mutant conidiated poorly, but this phenotype could be ameliorated by growth on osmotically stabilized media. The DeltarasA mutant also showed increased susceptibility to cell wall stressors, stained more intensely with calcofluor white, and was refractory to lysing enzymes used to make protoplasts, suggesting an alteration of the cell wall. All phenotypes associated with deletion of rasA could be corrected by reinsertion of the wild-type gene. These data demonstrate a crucial role for RasA in both hyphal growth and asexual development in A. fumigatus and provide evidence that RasA function is linked to cell wall integrity.
Authors:
Jarrod R Fortwendel; Kevin K Fuller; Timothy J Stephens; W Clark Bacon; David S Askew; Judith C Rhodes
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2008-07-07
Journal Detail:
Title:  Eukaryotic cell     Volume:  7     ISSN:  1535-9786     ISO Abbreviation:  Eukaryotic Cell     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-09-08     Completed Date:  2008-10-30     Revised Date:  2013-06-05    
Medline Journal Info:
Nlm Unique ID:  101130731     Medline TA:  Eukaryot Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1530-9     Citation Subset:  IM    
Affiliation:
Department of Pathology, University of Cincinnati, P.O. Box 670529, Cincinnati, OH 45267-0529, USA.
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MeSH Terms
Descriptor/Qualifier:
Aspergillus fumigatus / genetics,  growth & development*,  metabolism*
Cell Wall / genetics,  metabolism*
Cyclic AMP / metabolism
Fungal Proteins / genetics,  metabolism*
Gene Expression Regulation, Fungal*
Hyphae / genetics,  growth & development,  metabolism
Sequence Deletion
Spores, Fungal / genetics,  growth & development,  metabolism
ras Proteins / genetics,  metabolism*
Grant Support
ID/Acronym/Agency:
AI061495/AI/NIAID NIH HHS; AI061497/AI/NIAID NIH HHS
Chemical
Reg. No./Substance:
0/Fungal Proteins; 60-92-4/Cyclic AMP; EC 3.6.5.2/ras Proteins
Comments/Corrections

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