| Autor: |
Baasiri RA; Department of Microbiology and Molecular Genetics, University of Texas-Houston Medical School 77030, USA., Lu X, Rowley PS, Turner GE, Borkovich KA |
| Jazyk: |
angličtina |
| Zdroj: |
Genetics [Genetics] 1997 Sep; Vol. 147 (1), pp. 137-45. |
| DOI: |
10.1093/genetics/147.1.137 |
| Abstrakt: |
Heterotrimeric G proteins, consisting of alpha, beta and gamma subunits, mediate a variety of signaling pathways in eukaryotes. We have previously identified two genes, gna-1 and gna-2, that encode G protein alpha subunits in the filamentous fungus Neurospora crassa. Mutation of gna-1 results in female infertility and sensitivity to hyperosmotic media. In this study, we investigate the expression and functions of gna-2. Results from Western analysis and measurements of gna-2 promoter-lacZ fusion activity indicate that gna-2 is expressed during the vegetative and sexual cycle of N. crassa in both A and a mating types. Activating mutations predicted to abolish the GTPase activity of GNA-2 cause subtle defects in aerial hyphae formation and conidial germination. Extensive phenotypic analysis of delta gna-2 strains did not reveal abnormalities during vegetative or sexual development. In contrast, deletion of gna-2 in a delta gna-1 strain accentuates the delta gna-1 phenotypes. delta gna-1 delta gna-2 strains have a slower rate of hyphal apical extension than delta gna-1 strains on hyperosmotic media. Moreover, delta gna-1 delta gna-2 mutants have more pronounced defects in female fertility than delta gna-1 strains. We propose that gna-1 and gna-2 have overlapping functions and may constitute a gene family. This is the first report of G protein alpha subunits with overlapping functions in eukaryotic microbes. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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