Mutational activation of a Galphai causes uncontrolled proliferation of aerial hyphae and increased sensitivity to heat and oxidative stress in Neurospora crassa.
Mutational activation of a Galphai causes uncontrolled proliferation of aerial hyphae and increased sensitivity to heat and oxidative stress in Neurospora crassa.
复制标题
Galphai 的突变激活会导致气生菌丝不受控制地增殖，并增加粗糙脉孢菌对热和氧化应激的敏感性。
DOI：
10.1093/genetics/151.1.107
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发表时间：
1999
期刊：
影响因子：
3.3
通讯作者：
Borkovich,KA
中科院分区：
文献类型：
--
作者：
Yang,Q;Borkovich,KA
Heterotrimeric G proteins, consisting of α, β, and γ subunits, transduce environmental signals through coupling to plasma membrane-localized receptors. We previously reported that the filamentous fungus Neurospora crassa possesses a Gα protein, GNA-1, that is a member of the Gαisuperfamily. Deletion of gna-1 leads to defects in apical extension, differentiation of asexual spores, sensitivity to hyperosmotic media, and female fertility. In addition, Δgna-1 strains have lower intracellular cAMP levels under conditions that promote morphological abnormalities. To further define the function of GNA-1 in signal transduction in N. crassa, we examined properties of strains with mutationally activated gna-1 alleles (R178C or Q204L) as the only source of GNA-1 protein. These mutations are predicted to inhibit the GTPase activity of GNA-1 and lead to constitutive signaling. In the sexual cycle, gna-1R178Cand gna-1Q204Lstrains are female-fertile, but produce fewer and larger perithecia than wild type. During asexual development, gna-1R178Cand gna-1Q204Lstrains elaborate abundant, long aerial hyphae, produce less conidia, and possess lower levels of carotenoid pigments in comparison to wild-type controls. Furthermore, gna-1R178Cand gna-1Q204Lstrains are more sensitive to heat shock and exposure to hydrogen peroxide than wild-type strains, while Δgna-1 mutants are more resistant. In contrast to Δgna-1 mutants, gna-1R178Cand gna-1Q204Lstrains have higher steady-state levels of cAMP than wild type. The results suggest that GNA-1 possesses several Gβγ-independent functions in N. crassa. We propose that GNA-1 mediates signal transduction pathway(s) that regulate aerial hyphae development and sensitivity to heat and oxidative stresses, possibly through modulation of cAMP levels.
