Overlapping functions for two G protein alpha subunits in Neurospora crassa.
Genetics
; 147(1): 137-45, 1997 Sep.
Article
em En
| MEDLINE
| ID: mdl-9286674
ABSTRACT
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.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Proteínas Fúngicas
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Regulação Fúngica da Expressão Gênica
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Proteínas de Ligação ao GTP
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Neurospora crassa
Idioma:
En
Ano de publicação:
1997
Tipo de documento:
Article