title: Characterization of proliferating cell nuclear antigen (PCNA) from pathogenic yeast Candida albicans and its functional analyses in S. cerevisiae.
abstract: BACKGROUND
  Proliferating cell nuclear antigen (PCNA/POL30) an essential protein forms a homotrimeric ring encircling dsDNA and serves as a molecular scaffold to recruit various factors during DNA replication, repair and recombination. According to Candida Genome Database (CGD), orf19.4616 sequence is predicted to encode C. albicans PCNA (CaPCNA) that has not been characterized yet.
  
  
  RESULTS
  Molecular modeling studies of orf19.4616 using S. cerevisiae PCNA sequence (ScPCNA) as a template, and its subsequent biochemical characterizations suggest that like other eukaryotic PCNAs, orf19.4616 encodes for a conventional homotrimeric sliding clamp. Further we showed by surface plasmon resonance that CaPCNA physically interacted with yeast DNA polymerase eta. Plasmid segregation in genomic knock out yeast strains showed that CaPCNA but not its G178S mutant complemented for cell survival. Unexpectedly, heterologous expression of CaPCNA in S. cerevisiae exhibited slow growth phenotypes, sensitivity to cold and elevated temperatures; and showed enhanced sensitivity to hydroxyurea and various DNA damaging agents in comparison to strain bearing ScPCNA. Interestingly, wild type strains of C. albicans showed remarkable tolerance to DNA damaging agents when compared with similarly treated yeast cells.
  
  
  CONCLUSIONS
  Despite structural and physiochemical similarities; we have demonstrated that there are distinct functional differences between ScPCNA and CaPCNA, and probably the ways both the strains maintain their genomic stability. We propose that the growth of pathogenic C. albicans which is evolved to tolerate DNA damages could be controlled effectively by targeting this unique fungal PCNA.
authors.affiliation: Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India.
authors.forename: Kodavati
authors.initials: K
authors.lastname: Manohar
authors.affiliation: Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, 751023, India. narottam_acharya@ils.res.in.
authors.forename: Narottam
authors.initials: N
authors.lastname: Acharya
mesh_terms: D002176:Candida albicans / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004249:DNA Damage; D004271:DNA, Fungal / Q000187:drug effects; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005816:Genetic Complementation Test; D008958:Models, Molecular; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D000099270:Y-Family DNA Polymerases
chemical_list: D004271:DNA, Fungal; D004259:DNA-Directed DNA Polymerase; D005656:Fungal Proteins; D018809:Proliferating Cell Nuclear Antigen; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases