title: A Family of Secretory Proteins Is Associated with Different Morphotypes in Cryptococcus neoformans.
abstract: Cryptococcus neoformans, an opportunistic human fungal pathogen, can undergo a yeast-to-hypha transition in response to environmental cues. This morphological transition is associated with changes in the expression of cell surface proteins. TheCryptococcuscell surface and secreted protein Cfl1 was the first identified adhesin in the Basidiomycota. Cfl1 has been shown to regulate morphology, biofilm formation, and intercellular communication. Four additional homologs ofCFL1are harbored by theCryptococcusgenome:DHA1,DHA2,CPL1, andCFL105The common features of this gene family are the conserved C-terminal SIGC domain and the presence of an N-terminal signal peptide. We found that all these Cfl1 homolog proteins are indeed secreted extracellularly. Interestingly, some of these secretory proteins display cell type-specific expression patterns: Cfl1 is hypha specific, Dha2 is yeast specific, and Dha1 (delayed hypersensitivity antigen 1) is expressed in all cell types but is particularly enriched at basidia. Interestingly, Dha1 is induced by copper limitation and suppressed by excessive copper in the medium. This study further attests to the physiological heterogeneity of theCryptococcusmating colony, which is composed of cells with heterogeneous morphotypes. The differential expression of these secretory proteins contributes to heterogeneity, which is beneficial for the fungus to adapt to changing environments.IMPORTANCEHeterogeneity in physiology and morphology is an important bet-hedging strategy for nonmobile microbes such as fungi to adapt to unpredictable environmental changes.Cryptococcus neoformans, a ubiquitous basidiomycetous fungus, is known to switch from the yeast form to the hypha form during sexual development. However, in a mating colony, only a subset of yeast cells switch to hyphae, and only a fraction of the hyphal subpopulation will develop into fruiting bodies, where meiosis and sporulation occur. Here, we investigated a basidiomycete-specific secretory protein family. We found that some of these proteins are cell type specific, thus contributing to the heterogeneity of a mating colony. Our study also demonstrates the importance of examining the protein expression pattern at the individual-cell level in addition to population gene expression profiling for the investigation of a heterogeneous community.
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, USA.
authors.forename: Rachana
authors.initials: R
authors.lastname: Gyawali
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, USA.
authors.forename: Srijana
authors.initials: S
authors.lastname: Upadhyay
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Way
authors.affiliation: Department of Biology, Texas A&M University, College Station, Texas, USA xlin@bio.tamu.edu.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Lin
mesh_terms: D000220:Adaptation, Biological; D018441:Biofilms / Q000254:growth & development; D051338:Cofilin 1 / Q000235:genetics / Q000378:metabolism; D003455:Cryptococcus neoformans / Q000166:cytology* / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D017353:Gene Deletion; D020869:Gene Expression Profiling; D049770:Genes, Mating Type, Fungal; D025301:Hyphae / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D008540:Meiosis; D009024:Morphogenesis; D010641:Phenotype; D012098:Reproduction; D013045:Species Specificity; D000071436:Thermotolerance; D014774:Virulence
chemical_list: D051338:Cofilin 1; D005656:Fungal Proteins
keywords: dimorphism; morphogenesis; morphotype; secretory proteins; sexual reproduction