Gene disruption in Cryptococcus neoformans and Cryptococcus gattii by in vitro transposition
- 219 Downloads
Cryptococcus neoformans and Cryptococcus gattii are basidiomycetous fungi that infect immunocompromised and immunocompetent people. We developed an insertional mutagenesis strategy for these species based on in vitro transposition and we tested the method by disrupting the URA5 gene in a strain of C. neoformans and the CAP10 gene in three strains of C. gattii. We targeted plasmid DNA containing the URA5 gene or plasmid DNA containing the CAP10 gene from genomic libraries from the shotgun sequencing project for the C. gatti strain WM276. In the latter case, the availability of the end sequences of the clones from the assembled genomic sequence allows rapid selection of target genes for disruption. Modified transposons containing the nourseothricin (NAT) or neomycin (Neo) resistance cassettes were randomly inserted into the target DNA by in vitro transposition. The disrupted genes were used for biolistic transformation and homologous integration was subsequently confirmed by PCR and Southern blot analysis. These results demonstrate that the emerging genomic resources, combined with in vitro transposition into plasmid DNAs from shotgun sequencing libraries or cloned PCR products, will facilitate high-throughput genetic analysis in Cryptococcus species.
KeywordsGene disruption Transposon Basidiomycetes Virulence factors
Funding was provided by the National Institute of Allergy and Infectious Disease (5RO1AI053721) and the Canadian Institutes of Health Research (CIHR) to JWK. WM276 shotgun sequencing was completed at the Michael Smith Genome Science Centre (GSC) with funding from Genome Canada to JWK. We thank the sequencing group at the GSC for construction of the libraries.
- Adachi K, Nelson GH, Peoples KA, Frank SA, Montenegro-Chamorro MV, DeZwaan TM, Ramamurthy L, Shuster JR, Hamer L, Tanzer MM (2002) Efficient gene identification and targeted gene disruption in the wheat blotch fungus Mycosphaerella graminicola using TAGKO. Curr Genet 42:123–127PubMedCrossRefGoogle Scholar
- Casadevall A, Perfect JR (1998) Cryptococcus neoformans. ASM Press, WashingtonGoogle Scholar
- Hamer L, Adachi K, Montenegro-Chamorro MV, Tanzer MM, Mahanty SK, Lo C, Tarpey RW, Skalchunes AR, Heiniger RW, Frank SA, Darveaux BA, Lampe DJ, Slater TM, Ramamurthy L, DeZwaan TM, Nelson GH, Shuster JR, Woessner J, Hamer JE (2001) Gene discovery and gene function assignment in filamentous fungi. Proc Natl Acad Sci USA 98:5110–5115PubMedCrossRefGoogle Scholar
- Kidd SE, Hagen F, Tscharke RL, Huynh M, Bartlett KH, Fyfe M, Macdougall L, Boekhout T, Kwon-Chung KJ, Meyer W (2004) A rare genotype of Cryptococcus gattii caused the cryptococcosis outbreak on Vancouver Island (British Columbia, Canada). Proc Natl Acad Sci USA 101:17258–17263PubMedCrossRefGoogle Scholar
- Loftus BJ, Fung E, Roncaglia P, Rowley D, Amedeo P, Bruno D, Vamathevan J, Miranda M, Anderson IJ, Fraser JA, Allen JE, Bosdet IE, Brent MR, Chiu R, Doering TL, Donlin MJ, D’Souza CA, Fox DS, Grinberg V, Fu J, Fukushima M, Haas BJ, Huang JC, Janbon G, Jones SJ, Koo HL, Krzywinski MI, Kwon-Chung JK, Lengeler KB, Maiti R, Marra MA, Marra RE, Mathewson CA, Mitchell TG, Pertea M, Riggs FR, Salzberg SL, Schein JE, Shvartsbeyn A, Shin H, Shumway M, Specht CA, Suh BB, Tenney A, Utterback TR, Wickes BL, Wortman JR, Wye NH, Kronstad JW, Lodge JK, Heitman J, Davis RW, Fraser CM, Hyman RW (2005) The genome of the basidiomycetous yeast and human pathogen Cryptococcus neoformans Science 307:1321–1324PubMedCrossRefGoogle Scholar