Cryptococcus neoformans is a human pathogen that causes life threatening meningoencephalitis in immunocompromised and immunocompetent hosts. The organism is haploid and has a defined sexual cycle, well developed molecular biology research tools, and robust animal models for virulence studies. The basic structure of the genome is well characterized, being about 20MB distributed over 12 to 14 chromosomes. Currently a genome consortium is sequencing the genome of one representative laboratory strain, JEC21. It is anticipated that the JEC21 sequence will be completed within 12 months. ? ? There is considerable diversity among C. neoformans isolates. Isolates have been divided into four serotypes which differ by 10% or more at the DNA sequence level. Debate continues over whether these serotypes (A, B, C, D) should be considered different varieties or species. What is important is that these serotypes differ in not only their polysaccharide capsular antigens, but also in physiological properties and in pathogenicity. ? ? The most direct and efficient way to address the underlying nature of variation and its relationship to pathogenicity in C. neoformans is a comparative genomics approach taking advantage of the JEC21 sequence, in comparison with the sequence of a serotype A clinical isolate. JEC21 is a laboratory adapted strain derived from a clinical isolate and an environmental isolate by 12 backcrosses and may be attenuated for virulence. We thus propose to determine and annotate the complete sequence of C. neoformans serotype A strain H99. Greater than 90% of all clinical isolates and 99% of all isolates from AIDS patients are of serotype A, and strain H99 is a well characterized clinical isolate. In collaboration with the Vancouver Genome Center, we have produced the preliminary material and results to establish the feasibility of completing the genome in the manner described in this application. We also propose developing the basic resources to exploit this comparative data, namely a careful analysis of the differences between these two strains and a series of microarrays for genotyping of Cryptococcus strains. The resulting data and material from this study will expand our knowledge of the nature of pathogenicity in this important human fungal pathogen. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS042263-01A2
Application #
6616451
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Program Officer
Nunn, Michael
Project Start
2003-02-01
Project End
2007-01-31
Budget Start
2003-02-01
Budget End
2004-01-31
Support Year
1
Fiscal Year
2003
Total Cost
$365,750
Indirect Cost
Name
Duke University
Department
Genetics
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Janbon, Guilhem; Ormerod, Kate L; Paulet, Damien et al. (2014) Analysis of the genome and transcriptome of Cryptococcus neoformans var. grubii reveals complex RNA expression and microevolution leading to virulence attenuation. PLoS Genet 10:e1004261
Stajich, Jason E; Dietrich, Fred S; Roy, Scott W (2007) Comparative genomic analysis of fungal genomes reveals intron-rich ancestors. Genome Biol 8:R223
Stajich, Jason E; Dietrich, Fred S (2006) Evidence of mRNA-mediated intron loss in the human-pathogenic fungus Cryptococcus neoformans. Eukaryot Cell 5:789-93