THE ALS GENE FAMILY OF CANDIDA ALBICANS

Summary

Principal Investigator: LOIS HOYER
Affiliation: University of Illinois
Country: USA
Abstract: This proposal describes our ongoing efforts to characterize the eight ALS (agglutinin-like sequence) genes of Candida albicans and determine the function of their encoded proteins. In the previous funding period, we generated a set of alsA/alsA mutant strains and evaluated their phenotype in assays for adhesion to host cells and molecules, and for their ability to cause damage in disease models. Data showed that several of the Als proteins contribute to adhesion of C. albicans to host surfaces and suggested other intriguing roles for the Als proteins. This competing continuation application includes experiments that utilize well-characterized Als proteins to define adhesive function at the molecular level and also pursues investigations to define the multifunctional nature of the Als family. In Aim 1, the strong adhesive function of AlsSp is exploited to isolate the host cell proteins to which it binds; experiments to demonstrate the specificity of the interaction are also described. Surface plasmon resonance is utilized to further characterize these molecular interactions and random mutagenesis is used to define amino acids required for adhesive function. The focus of Aim 2 is ranking Als2p within the Als family for its relative contribution to adhesion to host cells and also to further define the role of Als2p and Alslp in regulation of C. albicans cell size. Aim 3 expands on previous experiments that showed that mutagenesis of ALS5, ALS6 or ALS7 resulted in increased adhesion of C. albicans to host surfaces. Previous microarray analysis showed that deletion of these genes results in up-regulation of other C. albicans cell wall proteins that might have adhesive function. Aim 4 makes use of our large collection of ALS-related strains and constructs to produce Als protein-specific monoclonal antibodies. These antibodies will be used to define Als protein localization on the surface of various C. albicans morphological forms, during cell mating, and on fungal cells from various animal disease models. We will also use the antibodies to support our conclusions about the role of Als proteins in C. albicans adhesion to host surfaces. Data from these studies are key to understanding Als adhesive interactions at the molecular level and understanding the breadth of function within the Als family.
Funding Period: 2000-09-20 - 2011-04-30
more information: NIH RePORT

Top Publications

  1. pmc Comparison between Candida albicans agglutinin-like sequence gene expression patterns in human clinical specimens and models of vaginal candidiasis
    Georgina Cheng
    Department of Veterinary Pathobiology, University of Illinois, Urbana, 2522 VMBSB, 2001 S Lincoln Avenue, Urbana, IL 61802, USA
    Infect Immun 73:1656-63. 2005
  2. pmc Recognition of Candida albicans Als3 by the germ tube-specific monoclonal antibody 3D9.3
    Bertrand Beucher
    Groupe d Etude des Interactions Hote Pathogene, UPRES EA 3142, UFR des Sciences Pharmaceutiques et d Ingénierie de la Santé, Angers, France
    FEMS Immunol Med Microbiol 55:314-23. 2009
  3. pmc Inhibition of Candida albicans adhesion by recombinant human antibody single-chain variable fragment specific for Als3p
    Sonia S Laforce-Nesbitt
    Department of Pediatrics, Women and Infants Hospital of Rhode Island, Warren Alpert Medical School of Brown University, Providence, RI 02905, USA
    FEMS Immunol Med Microbiol 54:195-202. 2008
  4. pmc Discovering the secrets of the Candida albicans agglutinin-like sequence (ALS) gene family--a sticky pursuit
    Lois L Hoyer
    Department of Pathobiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
    Med Mycol 46:1-15. 2008
  5. pmc Deletion of ALS5, ALS6 or ALS7 increases adhesion of Candida albicans to human vascular endothelial and buccal epithelial cells
    Xiaomin Zhao
    Department of Pathobiology, University of Illinois, Urbana, Illinois 61802, USA
    Med Mycol 45:429-34. 2007
  6. pmc Analysis of ALS5 and ALS6 allelic variability in a geographically diverse collection of Candida albicans isolates
    Xiaomin Zhao
    Department of Pathobiology, University of Illinois at Urbana Champaign, Urbana, IL 61802, USA
    Fungal Genet Biol 44:1298-309. 2007
  7. pmc Unequal contribution of ALS9 alleles to adhesion between Candida albicans and human vascular endothelial cells
    Xiaomin Zhao
    Department of Pathobiology, University of Illinois, Urbana, IL 61802, USA
    Microbiology 153:2342-50. 2007
  8. pmc Candida albicans Als3p is required for wild-type biofilm formation on silicone elastomer surfaces
    Xiaomin Zhao
    Department of Pathobiology, 2522 VMBSB, 2001 S Lincoln Avenue, University of Illinois, Urbana, IL 61802, USA
    Microbiology 152:2287-99. 2006
  9. pmc RT-PCR analysis of Candida albicans ALS gene expression in a hyposalivatory rat model of oral candidiasis and in HIV-positive human patients
    Clayton B Green
    Department of Pathobiology, University of Illinois, Urbana, Illinois 61802, USA
    Med Mycol 44:103-11. 2006
  10. pmc Cellular and molecular biology of Candida albicans estrogen response
    Georgina Cheng
    Department of Pathobiology, 2522 VMBSB, 2001 S Lincoln Avenue, Urbana, Illinois 61802, USA
    Eukaryot Cell 5:180-91. 2006

Scientific Experts

  • Lois L Hoyer
  • Bertrand Beucher
  • Xiaomin Zhao
  • Soon Hwan Oh
  • Clayton B Green
  • Georgina Cheng
  • Kathleen M Yeater
  • David R Soll
  • David A Coleman
  • Sonia S Laforce-Nesbitt
  • Robert Jajko
  • Claude Pujol
  • Karla J Daniels
  • Rui Zhao
  • X Zhao
  • Jeff T Hutchins
  • Hongyuan Zhao
  • Joseph M Patti
  • John H Vernachio
  • Joseph M Bliss
  • Mark A Sullivan
  • Michael A Pfaller
  • Daniel J Diekema
  • Sandra Manfra Marretta
  • E J Ehrhart
  • Fady F Faddoul
  • Jennifer A Nuessen
  • S H Oh
  • Suzanne R Trupin
  • Paul L Fidel
  • Shawn R Lockhart
  • Karen Wozniak
  • Matthew A Wallig
  • K M Yeater

Detail Information

Publications16

  1. pmc Comparison between Candida albicans agglutinin-like sequence gene expression patterns in human clinical specimens and models of vaginal candidiasis
    Georgina Cheng
    Department of Veterinary Pathobiology, University of Illinois, Urbana, 2522 VMBSB, 2001 S Lincoln Avenue, Urbana, IL 61802, USA
    Infect Immun 73:1656-63. 2005
    ..The data presented here support the conclusion of host-site-specific influences on ALS gene expression and validate the use of the experimental models for evaluating the phenotype of als/als mutant strains...
  2. pmc Recognition of Candida albicans Als3 by the germ tube-specific monoclonal antibody 3D9.3
    Bertrand Beucher
    Groupe d Etude des Interactions Hote Pathogene, UPRES EA 3142, UFR des Sciences Pharmaceutiques et d Ingénierie de la Santé, Angers, France
    FEMS Immunol Med Microbiol 55:314-23. 2009
    ..3 for differentiation between C. albicans and C. dubliniensis. Adhesion assays demonstrated that MAb 3D9.3 blocks adhesion of C. albicans germ tubes to human buccal epithelial cells and vascular endothelial cells...
  3. pmc Inhibition of Candida albicans adhesion by recombinant human antibody single-chain variable fragment specific for Als3p
    Sonia S Laforce-Nesbitt
    Department of Pediatrics, Women and Infants Hospital of Rhode Island, Warren Alpert Medical School of Brown University, Providence, RI 02905, USA
    FEMS Immunol Med Microbiol 54:195-202. 2008
    ..The altered pattern of immunostaining with other scFv that retain binding to the als3Delta/als3Delta mutant suggest that Als3p may also have a role in structural organization of the C. albicans cell surface...
  4. pmc Discovering the secrets of the Candida albicans agglutinin-like sequence (ALS) gene family--a sticky pursuit
    Lois L Hoyer
    Department of Pathobiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
    Med Mycol 46:1-15. 2008
    ..albicans at the genomic level, and the ALS family en masse, have advanced knowledge of these genes and emphasized their importance in C. albicans biology and pathogenesis...
  5. pmc Deletion of ALS5, ALS6 or ALS7 increases adhesion of Candida albicans to human vascular endothelial and buccal epithelial cells
    Xiaomin Zhao
    Department of Pathobiology, University of Illinois, Urbana, Illinois 61802, USA
    Med Mycol 45:429-34. 2007
    ..These studies demonstrate similar phenotypic characteristics for the als5Delta/als5Delta, als6Delta/als6Delta and als7Delta/als7Delta strains that are not observed in any of the other C. albicans alsDelta/alsDelta isolates...
  6. pmc Analysis of ALS5 and ALS6 allelic variability in a geographically diverse collection of Candida albicans isolates
    Xiaomin Zhao
    Department of Pathobiology, University of Illinois at Urbana Champaign, Urbana, IL 61802, USA
    Fungal Genet Biol 44:1298-309. 2007
    ..Natural deletion of ALS5 and the sequence variation within its coding region suggest relaxed selective pressure on this locus, and that Als5p function may be dispensable in C. albicans or redundant within the Als family...
  7. pmc Unequal contribution of ALS9 alleles to adhesion between Candida albicans and human vascular endothelial cells
    Xiaomin Zhao
    Department of Pathobiology, University of Illinois, Urbana, IL 61802, USA
    Microbiology 153:2342-50. 2007
    ..These data suggest greater selective pressure to maintain the ALS9-2 allele in C. albicans isolates and imply its greater relative importance in host-pathogen interactions...
  8. pmc Candida albicans Als3p is required for wild-type biofilm formation on silicone elastomer surfaces
    Xiaomin Zhao
    Department of Pathobiology, 2522 VMBSB, 2001 S Lincoln Avenue, University of Illinois, Urbana, IL 61802, USA
    Microbiology 152:2287-99. 2006
    ..albicans cells in the biofilm had yeast-like morphology. This result uncouples the effect of cellular morphology from biofilm formation and underscores the importance of Als3p in biofilm development on silicone elastomer surfaces...
  9. pmc RT-PCR analysis of Candida albicans ALS gene expression in a hyposalivatory rat model of oral candidiasis and in HIV-positive human patients
    Clayton B Green
    Department of Pathobiology, University of Illinois, Urbana, Illinois 61802, USA
    Med Mycol 44:103-11. 2006
    ..Overall, the patterns of ALS gene expression were similar between the rat model and human clinical specimens, suggesting that the model would be useful for studying the phenotype of al delta/al delta mutant strains...
  10. pmc Cellular and molecular biology of Candida albicans estrogen response
    Georgina Cheng
    Department of Pathobiology, 2522 VMBSB, 2001 S Lincoln Avenue, Urbana, Illinois 61802, USA
    Eukaryot Cell 5:180-91. 2006
    ..The cell biology and gene expression data from this study led to a model that proposes how components of the phospholipid and sterol metabolic pathways may interact to affect C. albicans germ tube formation and length...
  11. pmc Unique aspects of gene expression during Candida albicans mating and possible G(1) dependency
    Rui Zhao
    Department of Biological Sciences, 302 BBE, The University of Iowa, Iowa City, IA 52242, USA
    Eukaryot Cell 4:1175-90. 2005
    ..These results add to the lists of similarities and dissimilarities between the mating processes of C. albicans and S. cerevisiae and underscore the unique regulation of filamentation and switching genes in the C. albicans mating process...
  12. pmc Analysis of the Candida albicans Als2p and Als4p adhesins suggests the potential for compensatory function within the Als family
    X Zhao
    Department of Veterinary Pathobiology, University of Illinois at Urbana Champaign, Urbana, IL 61802, USA
    Microbiology 151:1619-30. 2005
    ..8-fold increase in ALS2 expression in the als4Delta/als4Delta strain and a 3.2-fold increase in ALS4 expression in the als2Delta/PMAL2-ALS2 strain, suggesting the potential for compensatory function between these related proteins...
  13. ncbi Construction and real-time RT-PCR validation of Candida albicans PALS-GFP reporter strains and their use in flow cytometry analysis of ALS gene expression in budding and filamenting cells
    Clayton B Green
    Department of Veterinary Pathobiology, University of Illinois at Urbana Champaign, Urbana, IL 61802, USA
    Microbiology 151:1051-60. 2005
    ..Assuming a positive correlation between transcriptional level and protein production, these results suggest that some Als proteins are abundant on the C. albicans cell surface while others are produced at a much lower level...
  14. ncbi Functional specificity of Candida albicans Als3p proteins and clade specificity of ALS3 alleles discriminated by the number of copies of the tandem repeat sequence in the central domain
    Soon Hwan Oh
    Department of Veterinary Pathobiology, University of Illinois at Urbana Champaign, Urbana, IL 61802, USA
    Microbiology 151:673-81. 2005
    ..The allelic variability observed for ALS3 and its functional consequences observed in strain SC5314 highlight the importance of understanding ALS allelic diversity in order to draw accurate conclusions about Als protein function...
  15. pmc Use of green fluorescent protein and reverse transcription-PCR to monitor Candida albicans agglutinin-like sequence gene expression in a murine model of disseminated candidiasis
    Clayton B Green
    Department of Veterinary Pathobiology, University of Illinois, Urbana, IL 61802, USA
    Infect Immun 73:1852-5. 2005
    ..GFP production from the ALS1 and ALS3 promoters was detected immunohistochemically. ALS1, ALS2, ALS3, ALS4, and ALS9 transcription was detected by RT-PCR, further identifying ALS genes expressed in this model...
  16. pmc Monoclonal antibodies specific for Candida albicans Als3 that immunolabel fungal cells in vitro and in vivo and block adhesion to host surfaces
    David A Coleman
    Department of Pathobiology, University of Illinois, Urbana, IL 61802, USA
    J Microbiol Methods 78:71-8. 2009
    ..albicans adhesion to vascular endothelial cells and buccal epithelial cells. These versatile MAbs are a valuable addition to the reagents available to study C. albicans cell surface dynamics and interaction of the fungus with host cells...