The GanB Galpha-protein negatively regulates asexual sporulation and plays a positive role in conidial germination in Aspergillus nidulans.
We isolated the ganB gene encoding the Galpha-protein homolog from Aspergillus nidulans. To investigate the cellular function of GanB, various mutant strains were isolated. Deletion of constitutively inactive ganB mutants showed conidiation and derepressed brlA expression in a submerged culture. Constitutive activation of GanB caused a reduction in hyphal growth and a severe defect in asexual sporulation. We therefore propose that GanB may negatively regulate asexual sporulation through the BrlA pathway. In addition, deletion or constitutive inactivation of GanB reduced germination rate while constitutive activation led to precocious germination. Furthermore, conidia of a constitutively active mutant could germinate even without carbon source. Taken together, these results indicated that GanB plays a positive role during germination, possibly through carbon source sensing, and negatively regulates asexual conidiation in A. nidulans.
Division of Biological Sciences, Chonbuk National University, Chonju 561-756, Republic of Korea.
Mi-Hee
MH
Chang
Keon-Sang
KS
Chae
Dong-Min
DM
Han
Kwang-Yeop
KY
Jahng
D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D017931:DNA Primers; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D005838:Genotype; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D012100:Reproduction, Asexual / Q000235:genetics*; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics; D013045:Species Specificity; D013170:Spores / Q000235:genetics / Q000502:physiology*; D014170:Transformation, Genetic
D017931:DNA Primers; D044385:GTP-Binding Protein alpha Subunits