The Aspergillus nidulans swoK1 mutant is defective in polarity maintenance when grown at restrictive temperature (38C). Upon germination, the swoK1 mutant extends a primary germ tube that swells to an enlarged, non-uniform cell with pronounced wall thickenings. The mutant is fully restored to wild type growth when transformed with a plasmid containing the gene An5802.2 as designated in The Broad Institute A. nidulans genomic database. The locus in the swoK1 mutant contains a single base deletion (G) 545 bp downstream from the predicted start codon that results in a frame-shift that is predicted to terminate in a stop codon 18 amino acids down stream of the lesion. The SwoK predicted protein contains an N-terminal RRM (RNA Recognition motif) and a highly repetitive C-terminus with SR repeats and RD repeats. The SwoK protein is 43% identical to the S. pombe protein Srp1. The proteins each contain the N-terminal RRM and in the SR repeats, but SRP1 does not contain the RD repeats. In S. pombe Srp1 is both an RNA splicing factor and responsible for RNA translocation out of the nucleus. Full length homologs of this protein are found in the filamentous fungal genomes of N. crassa and M. grisea. The possible role of this protein in polarized development will be discussed.
Full conference title:
23rd Fungal Genetics Conference
- Fungal Genetics Conference 23rd (2002)