Jenull, SabrinaTscherner, MichaelGulati, MeghaNobile, Clarissa J.Chauhan, NeerajKuchler, Karl2017-11-212017Jenull, Sabrina, Michael Tscherner, Megha Gulati, Clarissa J. Nobile, Neeraj Chauhan, and Karl Kuchler. 2017. “The Candida albicans HIR histone chaperone regulates the yeast-to-hyphae transition by controlling the sensitivity to morphogenesis signals.” Scientific Reports 7 (1): 8308. doi:10.1038/s41598-017-08239-9. http://dx.doi.org/10.1038/s41598-017-08239-9.http://nrs.harvard.edu/urn-3:HUL.InstRepos:34375070Morphological plasticity such as the yeast-to-hyphae transition is a key virulence factor of the human fungal pathogen Candida albicans. Hyphal formation is controlled by a multilayer regulatory network composed of environmental sensing, signaling, transcriptional modulators as well as chromatin modifications. Here, we demonstrate a novel role for the replication-independent HIR histone chaperone complex in fungal morphogenesis. HIR operates as a crucial modulator of hyphal development, since genetic ablation of the HIR complex subunit Hir1 decreases sensitivity to morphogenetic stimuli. Strikingly, HIR1-deficient cells display altered transcriptional amplitudes upon hyphal initiation, suggesting that Hir1 affects transcription by establishing transcriptional thresholds required for driving morphogenetic cell-fate decisions. Furthermore, ectopic expression of the transcription factor Ume6, which facilitates hyphal maintenance, rescues filamentation defects of hir1Δ/Δ cells, suggesting that Hir1 impacts the early phase of hyphal initiation. Hence, chromatin chaperone-mediated fine-tuning of transcription is crucial for driving morphogenetic conversions in the fungal pathogen C. albicans.en-USJournal Article2017-11-2110.1038/s41598-017-08239-9