The Neurospora rca-1 gene complements an Aspergillus flbD sporulation mutant but has no identifiable role in Neurospora sporulation.
The Aspergillus nidulans flbD gene encodes a protein with a Myb-like DNA-binding domain that is proposed to act in concert with other developmental regulators to control initiation of conidiophore development. We have identified a Neurospora crassa gene called rca-1 (regulator of conidiation in Aspergillus) based on its sequence similarity to flbD. We found that N. crassa rca-1 can complement the conidiation defect of an A. nidulans flbD mutant and that induced expression of rca-1 caused conidiation in submerged A. nidulans cultures just as was previously observed for overexpression of flbD. Thus, the N. crassa gene appears to be a functional homologue of A. nidulans flbD and this is the first demonstration of functional complementation of an A. nidulans sporulation defect using a gene from an evolutionarily distant fungus. However, deletion of the rca-1 gene in N. crassa had no major effect on growth rate, macroconidiation, microconidiation, or ascospore formation. The only phenotype displayed by the rca-1 mutant was straight or counterclockwise hyphal growth rather than the clockwise spiral growth observed for wild type. Thus, if rca-1 is involved in N. crassa development, its role is subtle or redundant.
Shen
W C
WC
Program for the Biology of Filamentous Fungi, Texas A&M University, College Station 77843-2132, USA.
Wieser
J
J
Adams
T H
TH
Ebbole
D J
DJ
D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D003001:Cloning, Molecular; D004271:DNA, Fungal; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics*; D017353:Gene Deletion; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009492:Neurospora crassa / Q000235:genetics* / Q000254:growth & development; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics*
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C112194:Rca-1 protein, Neurospora crassa; D015534:Trans-Activators; C092469:flbD protein, Aspergillus nidulans