Rad52 depletion in Candida albicans triggers both the DNA-damage checkpoint and filamentation accompanied by but independent of expression of hypha-specific genes.
We have analysed the effect of RAD52 deletion in several aspects of the cell biology of Candida albicans. Cultures of rad52Delta strains exhibited slow growth and contained abundant cells with a filamentous morphology. Filamentation with polarization of actin patches was accompanied by the induction of the hypha-specific genes (HSG) ECE1, HWP1 and HGC1. However, filament formation occurred in the absence of the transcription factors Efg1 and Cph1, even though disruption of EFG1 prevented expression of HSG. Therefore, expression of HSG genes accompanies but is dispensable for rad52Delta filamentation. However, deletion of adenylate cyclase severely impaired filamentation, this effect being largely reverted by the addition of exogenous cAMP. Filaments resembled elongated pseudohyphae, but some of them looked like true hyphae. Following depletion of Rad52, many cells arrested at the G2/M phase of the cell cycle with a single nucleus suggesting the early induction of the DNA-damage checkpoint. Filaments formed later, preferentially from G2/M cells. The filamentation process was accompanied by the uncoupling of several landmark events of the cell cycle and was partially dependent on the action of the cell cycle modulator Swe1. Hyphae were still induced by serum, but a large number of rad52 cells myceliated in G2/M.
Departamento de Microbiología, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain.
Encarnación
E
Andaluz
Toni
T
Ciudad
Jonathan
J
Gómez-Raja
Richard
R
Calderone
Germán
G
Larriba
D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism; D002176:Candida albicans / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology; D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics; D049109:Cell Proliferation; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D051721:Rad52 DNA Repair and Recombination Protein / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
C090837:CPH1 protein, Candida albicans; D018797:Cell Cycle Proteins; D016213:Cyclins; D004268:DNA-Binding Proteins; C121438:EFG1 protein, Candida albicans; D005656:Fungal Proteins; C118102:HWP1 protein, Candida albicans; D008562:Membrane Glycoproteins; D051721:Rad52 DNA Repair and Recombination Protein; D014157:Transcription Factors; D011505:Protein-Tyrosine Kinases; D000262:Adenylyl Cyclases