ALL2, a Homologue of ALL1, Has a Distinct Role in Regulating pH Homeostasis in the Pathogen Cryptococcus neoformans.
Infect Immun, 2016/02;84(2):439-51.
Jain N[1], Bouklas T[2], Gupta A[1], Varshney AK[2], Orner EP[3], Fries BC[4]
Affiliations
PMID: 26597983DOI: 10.1128/IAI.01046-15
Impact factor: 3.609
Abstract
Cryptococcus neoformans is a facultative intracellular fungal pathogen that has a polysaccharide capsule and causes life-threatening meningoencephalitis. Its capsule, as well as its ability to survive in the acidic environment of the phagolysosome, contributes to the pathogen's resilience in the host environment. Previously, we reported that downregulation of allergen 1 (ALL1) results in the secretion of a shorter, more viscous exopolysaccharide with less branching and structural complexity, as well as altered iron homeostasis. Now, we report on a homologous coregulated gene, allergen 2 (ALL2). ALL2's function was characterized by generating null mutants in C. neoformans. In contrast to ALL1, loss of ALL2 attenuated virulence in the pulmonary infection model. The all2Δ mutant shed a less viscous exopolysaccharide and exhibited higher sensitivity to hydrogen peroxide than the wild type, and as a result, the all2Δ mutant was more resistant to macrophage-mediated killing. Transcriptome analysis further supported the distinct function of these two genes. Unlike ALL1's involvement in iron homeostasis, we now present data on ALL2's unique function in maintaining intracellular pH in low-pH conditions. Thus, our data highlight that C. neoformans, a human-pathogenic basidiomycete, has evolved a unique set of virulence-associated genes that contributes to its resilience in the human niche.
MeSH terms
Allergens; Animals; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Fungal Proteins; Homeostasis; Humans; Hydrogen Peroxide; Hydrogen-Ion Concentration; Lung; Mice, Inbred BALB C; Microarray Analysis; Molecular Sequence Data; Mutation; Phenotype; Vacuoles; Virulence Factors
More resources
Full text:
Europe PubMed Central; PubMed Central
EndNote: Download