Biased eviction of variant histone H3 nucleosomes triggers biofilm growth in Candida albicans

In this study, we utilized genome-wide MNase-seq, ATAC-seq, and MNase ChIP-seq techniques to investigate how nucleosomes contribute to gene expression regulation during transition from planktonic to biofilm cells in C. albicans. We have previously identified a variant of histone H3, H3VCTG, which acts as a negative regulator of biofilm formation in planktonic cells. In the current study, we found that H3VCTG occludes the binding sites of transcription factors in planktonic cells and lacks the post-translational modifications associated with actively transcribing histone H3 marks. Interestingly, we observed a significant decrease in the total number of nucleosomes in the biofilm cells resulting in an open chromatin landscape, as compared to the cells grown in the planktonic conditions. Additionally, we have also observed a biased removal of histone h3 variant nucleosomes from the promoters of biofilm-relevant genes, thereby aiding the formation of biofilms in C. albicans.