Cyclin Cln3p links G1 progression to hyphal and pseudohyphal development in Candida albicans.
G1 cyclins coordinate environmental conditions with growth and differentiation in many organisms. In the pathogen Candida albicans, differentiation of hyphae is induced by environmental cues but in a cell cycle-independent manner. Intriguingly, repressing the G1 cyclin Cln3p under yeast growth conditions caused yeast cells to arrest in G1, increase in size, and then develop into hyphae and pseudohyphae, which subsequently resumed the cell cycle. Differentiation was dependent on Efg1p, Cph1p, and Ras1p, but absence of Ras1p was also synthetically lethal with repression of CLN3. In contrast, repressing CLN3 in environment-induced hyphae did not inhibit growth or the cell cycle, suggesting that yeast and hyphal cell cycles may be regulated differently. Therefore, absence of a G1 cyclin can activate developmental pathways in C. albicans and uncouple differentiation from the normal environmental controls. The data suggest that the G1 phase of the cell cycle may therefore play a critical role in regulating hyphal and pseudohyphal development in C. albicans.
Bachewich
Catherine
C
Health Sector, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada. cbachewi@alcor.concordia.ca
Whiteway
Malcolm
M
D015152:Blotting, Northern; D002176:Candida albicans / Q000378:metabolism*; D002453:Cell Cycle; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D016193:G1 Phase; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005838:Genotype; D009841:Oligonucleotides / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology*; D013696:Temperature; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism
C079895:CLN3 protein, S cerevisiae; C090837:CPH1 protein, Candida albicans; D016213:Cyclins; D004268:DNA-Binding Proteins; C121438:EFG1 protein, Candida albicans; D005656:Fungal Proteins; D009841:Oligonucleotides; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C489014:RAS1 protein, S cerevisiae; D018631:ras Proteins