Abstract: The present invention provides C. neoformans genes that are essential and are potential targets for drug screening. The nucleotide sequence of the target genes can be used for various drug discovery purposes, such as expression of the recombinant protein, hybridization assay and construction of nucleic acid arrays. The uses of proteins encoded by the essential genes, and genetically engineered cells comprising modified alleles of essential genes in various screening methods are also encompassed by the invention. The present invention also provides methods and compositions that enable the experimental determination as to whether any gene in the genome of Cryptococcus neoformans is essential, and whether that gene is required for virulence or pathogenicity. The identification of essential genes and those genes critical to the development of virulent infections, provides a basis for the development of screens for new drugs against C. neoformans.

Abstract: The present invention provides nucleotide sequences, methods and compositions that enable the experimental determination as to whether any gene in the genome of Aspegillus fumigatus is essential, and whether that gene is required for virulence or pathogenicity. The methods involve the construction of genetic mutants in which a target gene is placed under conditional expression. The identification of essential genes and those genes critical to the development of virulent infections, provides a basis for the development of screens for new drugs against Aspergillus fumigatus.