We isolated ganA and ganB encoding G alpha protein homologs fromAspergillus nidulans. To investigate the cellular function of these G proteins, we have constructed various mutants of ganA and ganB by gene targeting. The viscosity of culture broth of ganA dominant-activating mutant in which GanAp is constitutively activated was lower than that of wild type. The protoplasts were generated more rapidly in this mutant. However deletion, over-expression, or dominant interfering mutants of ganAhave shown no clear phenotype in growth and development. Meanwhile, ganB deletion or dominant-interfering mutants showed hyperactive sporulation phenotype and derepressedbrlA expression in submerged culture. Constitutive activation of GanBp caused reduction of hyphal growth and asexual sporulation. Cleistothecium formation was accelerated inganB over-expression mutants but reduced in ganB deletion and interfering mutants. Consequently, we suggest GanBp probably negative regulator of asexual sporulation resulting in progressing sexual development. In addition, ganB deletion or dominant-interfering mutation delayed conidial germination rate and dominant-activating mutation caused precocious germination even without carbon source, implying that GanBp might be involved in carbon source sensing required for conidial germination in A. nidulans.
Fungal Genet. Newsl. 50 (Supl):abstract
Full conference title:
22nd Fungal Genetics Conference
- Fungal Genetics Conference 22nd (2001)