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The transcription factor Sko1 represses the yeast-tohypha
transition and mediates the oxidative stress
response in Candida albicans.
Inês Correia, Elvira Román, David M. Arana, Daniel Prieto, Verónica
Urrialde, César Nombela, Rebeca Alonso-Monge and Jesús Pla. §
Departamento de Microbiología II. Facultad de Farmacia. Universidad Complutense de
Madrid. Plaza de Ramón y Cajal s/n. E-28040 MADRID. SPAIN
Cells adapt to external changes by triggering transcriptional responses. These
responses are complex and are mediated by different transcription factors. Mutants
lacking the transcription factor Sko1 were generated in Candida albicans and its
roles on the physiology of this opportunistic pathogen are reported. Genome-wide
transcriptional analysis revealed that Sko1 acts as a transcriptional repressor of
genes involved in pathogenesis and hyphal formation. The sko1 mutant displayed
an increased expression of the hyphal related genes ECE1 and HWP1 but showed
no drastic alterations in the mouse model of systemic infection. Deletion of SKO1
rendered mutants derepressed in the yeast-to-hypha transition. Moreover, Sko1
was shown to be involved in the response to oxidative stress and sko1 mutants
increased the sensitivity of hog1 mutants to the myelomonocytic cell line HL-60.
Alterations in the phosphorylation pattern of MAP kinase mutants in response to
oxidative challenge were also observed. Genome-wide transcriptional analysis after
hydrogen peroxide treatment revealed that sko1 mutants were able to generate an
adaptive response similar to wild type strains, although important differences were
detected in the magnitude of such transcriptional response. Collectively, these
results implicate Sko1 as a key mediator of the oxidative stress response and
morphological transition in C. albicans.
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