Identification of an exoribonuclease homolog, CaKEM1/CaXRN1, in Candida albicans and its characterization in filamentous growth.
KEM1/XRN1 and RAT1 are two known exoribonuclease genes in Saccharomyces cereivsiae and encode a cytoplasmic and nuclear exoribonuclease, respectively. CaKEM1/CaXRN1 and CaRAT1, the Candida albicans homologs of 5'-->3' exoribonuclease genes, were identified by protein sequence comparisons and by functional complementation of the S. cerevisiae kem1/xrn1 null mutation. The deduced amino acid sequences of CaKEM1 and CaRAT1 show 51% and 55% identities to those of the S. cerevisiae KEM1 and RAT1, respectively. The exonuclease motifs were found to be highly conserved in CaKem1p and CaRat1p. We disrupted two chromosomal copies of CaKEM1 in a diploid C. albicans strain and demonstrate that C. albicans kem1/kem1 mutants are defective in filamentous growth on filamentous-inducing media. These results imply that CaKEM1 is involved in filamentous growth of C. albicans.
An
Hae-Sook
HS
Department of Microbiology, College of Natural Sciences, Chungnam National University, Youseong-Gu, Gung-Dong 220, Daejeon 305-764, Republic of Korea.
Lee
Kang-Hoon
KH
Kim
Jinmi
J
D000595:Amino Acid Sequence; D002176:Candida albicans / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D003001:Cloning, Molecular; D005095:Exoribonucleases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005816:Genetic Complementation Test; D025301:Hyphae / Q000254:growth & development; D008969:Molecular Sequence Data; D009154:Mutation; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*
D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; C075577:RAT1 protein, S cerevisiae; D005095:Exoribonucleases; C068398:XRN1 protein, S cerevisiae