? DNA repair has not been studied in the human pathogen Candida albicans in spite of numerous observations that suggest extensive genomic variability among clinical isolates. This variability has been associated with a variety of genomic alterations that include, deletions, translocations, ploidy changes, as well as loss of chromosomes or parts of chromosomes. The relationship of these changes to adaptation, virulence, and growth of the fungus in the host is uncertain, but sugar utilization and drug resistance have been correlated in vitro with aneuloploidy. Homologous recombination [HR] and non-homologous end-joining [NHEJ] should be important components in DNA repair to ensure the fidelity of these genomic alterations. Our preliminary studies with Rad52p of the HR and Lig4p of the NHEJ pathways suggest that both proteins provide growth functions in addition to DNA repair in C. albicans. This fact along with the surprising genomic variability of this pathogen suggest differences between the DNA repair pathways of S. cerevisiae and C. albicans. To understand the roles of HR and NHEJ in this organism, we propose four specific aims.
Specific aim 1 includes the construction of new mutants in each of the two pathways, HDF1 in NHEJ and RAD59 in HR.
In specific aim 2, we will complete our analysis of PIF1 and RRM3, two proteins identified from a two-hybrid screen that interact with Lig4p. The role of HR and NHEJ pathway proteins in DNA repair and morphogenesis is the focus of specific aim 3. In addition, microarray analysis will be used to identify up and down regulated genes in selected mutants of C. albicans when compared to wild type cells. Finally, aim 4 is designed to evaluate the role of several gene deleted mutants in the pathogenesis of candidiasis. We propose to use three mouse models of candidiasis to evaluate virulence, including, invasive, oral, and vaginal models so as to identify a site-specific role of these genes in virulence. In summary, our studies will provide critical information on the contribution of DNA repair to the adaptation, growth, variability and virulence of C. albicans. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI051949-01A2
Application #
6695813
Study Section
AIDS and Related Research 8 (AARR)
Program Officer
Duncan, Rory A
Project Start
2003-07-01
Project End
2006-12-31
Budget Start
2003-07-01
Budget End
2003-12-31
Support Year
1
Fiscal Year
2003
Total Cost
$168,543
Indirect Cost
Name
Georgetown University
Department
Microbiology/Immun/Virology
Type
Schools of Dentistry
DUNS #
049515844
City
Washington
State
DC
Country
United States
Zip Code
20057
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Garcia-Prieto, Fatima; Gomez-Raja, Jonathan; Andaluz, Encarnacion et al. (2010) Role of the homologous recombination genes RAD51 and RAD59 in the resistance of Candida albicans to UV light, radiomimetic and anti-tumor compounds and oxidizing agents. Fungal Genet Biol 47:433-45
Gomez-Raja, Jonathan; Andaluz, Encarnacion; Magee, Beatrice et al. (2008) A single SNP, G929T (Gly310Val), determines the presence of a functional and a non-functional allele of HIS4 in Candida albicans SC5314: detection of the non-functional allele in laboratory strains. Fungal Genet Biol 45:527-41
Andaluz, Encarnacion; Gomez-Raja, Jonathan; Hermosa, Belen et al. (2007) Loss and fragmentation of chromosome 5 are major events linked to the adaptation of rad52-DeltaDelta strains of Candida albicans to sorbose. Fungal Genet Biol 44:789-98
Andaluz, Encarnacion; Ciudad, Toni; Gomez-Raja, Jonathan et al. (2006) Rad52 depletion in Candida albicans triggers both the DNA-damage checkpoint and filamentation accompanied by but independent of expression of hypha-specific genes. Mol Microbiol 59:1452-72
Chauhan, Neeraj; Ciudad, Toni; Rodriguez-Alejandre, Ane et al. (2005) Virulence and karyotype analyses of rad52 mutants of Candida albicans: regeneration of a truncated chromosome of a reintegrant strain (rad52/RAD52) in the host. Infect Immun 73:8069-78
Ciudad, Toni; Andaluz, Encarnacion; Steinberg-Neifach, Olga et al. (2004) Homologous recombination in Candida albicans: role of CaRad52p in DNA repair, integration of linear DNA fragments and telomere length. Mol Microbiol 53:1177-94