Histoplasma Amino Acid Transporters - Raw Data

The dimorphic fungus Histoplasma capsulatum, which almost exclusively resides within host phagocytic cells during infection, must meet its nutritional needs by scavenging molecules from the phagosome environment. The requirement for gluconeogenesis, but not fatty acid catabolism, for intracellular growth, implicates amino acids as a likely intracellular nutrient source. Consequently, we investigated the transcriptional response of Histoplasma yeast to growth on amino acids. In addition to core gluconeogenesis and amino acid catabolism genes, growth on amino acids was correlated with upregulation of several genes encoding Histoplasma virulence factors including Cbp1, Ctr3, CatB and CatP catalases, as well as the Ryp1 and Ryp2 transcription factors, which regulate Histoplasma pathogenic-phase genes. Growth assays demonstrated that Histoplasma yeasts readily utilize most amino acids as nitrogen sources but only efficiently catabolize glutamine, glutamate, aspartate, proline, isoleucine, and alanine as carbon sources. We characterized the substrate specificities of the major Histoplasma amino acid transporters using a Saccharomyces cerevisiae heterologous expression system and found that H. capsulatum Dip5, Gap3, and a newly described permease, Gai1, comprise most of Histoplasma’s amino acid import capacity. Histoplasma yeasts deficient in these three transporters are impaired for growth on free amino acids but proliferate within macrophages and remain fully virulent during infection of mice, indicating that free amino acids are not the principal nutrient source within the phagosome to support Histoplasma proliferation during infection.File Descriptions:raw data - Numerical data used to produce published figures.RNAseq data - EdgeR output and raw TPMs for Histoplasma gene features.