Global Role of the Protein Kinase Gcn2 in the Human Pathogen Candida albicans

ABSTRACT The pathogen Candida albicans responds to amino acid starvation by activating pseudohyphal development and the expression of amino acid biosynthetic genes (GCN response). In Saccharomyces cerevisiae, the GCN response is dependent on Gcn2, which regulates the translation of the transcription factor Gcn4. Therefore, we examined the role of Gcn2 in C. albicans by using molecular, cellular, and genomic approaches. We show that C. albicans GCN2 encodes an eIF2α kinase, like its S. cerevisiae homologue. However, GCN4 appears to be regulated mainly at the transcriptional level in C. albicans. Furthermore, the inactivation of C. albicans Gcn2 only partially attenuates growth under amino acid starvation conditions and resistance to the histidine analogue 3-aminotriazole. Our comparison of the Gcn4 and Gcn2 regulons by transcript profiling reinforces the view that Gcn2 contributes to, but is not essential for, the activation of general amino acid control in C. albicans.

[1]  A. Gillum,et al.  Isolation of the Candida albicans gene for orotidine-5′-phosphate decarboxylase by complementation of S. cerevisiae ura3 and E. coli pyrF mutations , 2004, Molecular and General Genetics MGG.

[2]  M Vingron,et al.  Transcriptional profiling on all open reading frames of Saccharomyces cerevisiae , 1998, Yeast.

[3]  M. Raymond,et al.  The bZip Transcription Factor Cap1p Is Involved in Multidrug Resistance and Oxidative Stress Response inCandida albicans , 1999, Journal of bacteriology.

[4]  N. Gow,et al.  GFP as a quantitative reporter of gene regulation in Candida albicans , 2004, Yeast.

[5]  Alistair J. P. Brown,et al.  Ectopic Expression of URA3 Can Influence the Virulence Phenotypes and Proteome of Candida albicans but Can Be Overcome by Targeted Reintegration of URA3 at the RPS10 Locus , 2004, Eukaryotic Cell.

[6]  C. Yanofsky,et al.  The cross-pathway control gene of Neurospora crassa, cpc-1, encodes a protein similar to GCN4 of yeast and the DNA-binding domain of the oncogene v-jun-encoded protein. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[7]  J. Berman,et al.  Cassettes for PCR‐mediated construction of green, yellow, and cyan fluorescent protein fusions in Candida albicans , 2001, Yeast.

[8]  S Falkow,et al.  Yeast-enhanced green fluorescent protein (yEGFP): a reporter of gene expression in Candida albicans. , 1997, Microbiology.

[9]  F. Odds,et al.  Candida and candidosis , 1979 .

[10]  G. Braus,et al.  The Aspergillus fumigatus transcriptional activator CpcA contributes significantly to the virulence of this fungal pathogen , 2004, Molecular microbiology.

[11]  Bing Guo,et al.  Ras Signaling Is Required for Serum-Induced Hyphal Differentiation in Candida albicans , 1999, Journal of bacteriology.

[12]  C. Mamoun,et al.  Candida albicans Csy1p Is a Nutrient Sensor Important for Activation of Amino Acid Uptake and Hyphal Morphogenesis , 2004, Eukaryotic Cell.

[13]  M. Whiteway,et al.  Stress-induced gene expression in Candida albicans: absence of a general stress response. , 2003, Molecular biology of the cell.

[14]  N. Martin,et al.  CandidaDB: a genome database for Candida albicans pathogenomics , 2004, Nucleic Acids Res..

[15]  M. Whiteway,et al.  Msn2- and Msn4-Like Transcription Factors Play No Obvious Roles in the Stress Responses of the Fungal Pathogen Candida albicans , 2004, Eukaryotic Cell.

[16]  G. Fink,et al.  Regulated degradation of the transcription factor Gcn4. , 1994, The EMBO journal.

[17]  G. Braus,et al.  Transcriptional autoregulation and inhibition of mRNA translation of amino acid regulator gene cpcA of filamentous fungus Aspergillus nidulans. , 2001, Molecular biology of the cell.

[18]  S. Macaskill,et al.  Gcn4 co‐ordinates morphogenetic and metabolic responses to amino acid starvation in Candida albicans , 2002, The EMBO journal.

[19]  A. Johnson,et al.  Control of filament formation in Candida albicans by the transcriptional repressor TUP1. , 1997, Science.

[20]  D. Irwin,et al.  Isogenic strain construction and gene mapping in Candida albicans. , 1993, Genetics.

[21]  M. Whiteway,et al.  Signaling through adenylyl cyclase is essential for hyphal growth and virulence in the pathogenic fungus Candida albicans. , 2001, Molecular biology of the cell.

[22]  D. Kornitzer,et al.  Coevolution of Cyclin Pcl5 and Its Substrate Gcn4 , 2005, Eukaryotic Cell.

[23]  P. Kozinn,et al.  Candida and candidiasis. , 1971, JAMA.

[24]  M. Schaller,et al.  Differential expression of secreted aspartyl proteinases in a model of human oral candidosis and in patient samples from the oral cavity , 1998, Molecular microbiology.

[25]  G. Fink,et al.  Suppression of hyphal formation in Candida albicans by mutation of a STE12 homolog. , 1994, Science.

[26]  R. Young,et al.  Negative regulation of Gcn4 and Msn2 transcription factors by Srb10 cyclin-dependent kinase. , 2001, Genes & development.

[27]  Alexander D. Johnson,et al.  Rfg1, a Protein Related to the Saccharomyces cerevisiae Hypoxic Regulator Rox1, Controls Filamentous Growth and Virulence in Candida albicans , 2001, Molecular and Cellular Biology.

[28]  G. Fink,et al.  Degradation of the transcription factor Gcn4 requires the kinase Pho85 and the SCF(CDC4) ubiquitin-ligase complex. , 2000, Molecular biology of the cell.

[29]  A. Hinnebusch.  Mechanisms of gene regulation in the general control of amino acid biosynthesis in Saccharomyces cerevisiae. , 1988, Microbiological reviews.

[30]  F. Sherman.  Getting started with yeast. , 1991, Methods in enzymology.

[31]  C. d’Enfert,et al.  Candida albicans Biofilms: a Developmental State Associated With Specific and Stable Gene Expression Patterns , 2004, Eukaryotic Cell.

[32]  A. Brown,et al.  NRG1 represses yeast–hypha morphogenesis and hypha‐specific gene expression in Candida albicans , 2001, The EMBO journal.

[33]  Paula Grisafi,et al.  Phagocytosis by neutrophils induces an amino acid deprivation response in Saccharomyces cerevisiae and Candida albicans , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[34]  C. Sensen,et al.  Transcription profiling of Candida albicans cells undergoing the yeast-to-hyphal transition. , 2002, Molecular biology of the cell.

[35]  O. Kurzai,et al.  Dominant Active Alleles of RIM101(PRR2) Bypass the pH Restriction on Filamentation ofCandida albicans , 2000, Molecular and Cellular Biology.

[36]  M. E. Gent,et al.  Transcript analysis of 1003 novel yeast genes using high‐throughput northern hybridizations , 2001, The EMBO journal.

[37]  Krishnamurthy Natarajan,et al.  Gcn4p, a Master Regulator of Gene Expression, Is Controlled at Multiple Levels by Diverse Signals of Starvation and Stress , 2002, Eukaryotic Cell.

[38]  B. R. Braun,et al.  NRG1, a repressor of filamentous growth in C.albicans, is down‐regulated during filament induction , 2001, The EMBO journal.

[39]  Alistair J. P. Brown,et al.  Fungal morphogenesis and host invasion. , 2002, Current opinion in microbiology.

[40]  R. Tibshirani,et al.  Significance analysis of microarrays applied to the ionizing radiation response , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[41]  G. Braus,et al.  The Aspergillus nigerGCN4 homologue, cpcA, is transcriptionally regulated and encodes an unusual leucine zipper , 1997, Molecular microbiology.

[42]  Stephen G Oliver,et al.  Proteomic response to amino acid starvation inCandida albicans and Saccharomyces cerevisiae , 2004, Proteomics.

[43]  C. Kumamoto.  Candida biofilms. , 2002, Current opinion in microbiology.

[44]  C. Nombela,et al.  The mitogen-activated protein kinase homolog HOG1 gene controls glycerol accumulation in the pathogenic fungus Candida albicans , 1996, Journal of bacteriology.

[45]  M. Marton,et al.  Transcriptional Profiling Shows that Gcn4p Is a Master Regulator of Gene Expression during Amino Acid Starvation in Yeast , 2001, Molecular and Cellular Biology.

[46]  G. Braus,et al.  Monitoring the Gcn4 Protein-mediated Response in the YeastSaccharomyces cerevisiae * , 1998, The Journal of Biological Chemistry.

[47]  A. Mitchell,et al.  RIM101-Dependent and -Independent Pathways Govern pH Responses in Candida albicans , 2000, Molecular and Cellular Biology.