High resolution genome-wide occupancy in Candida species using ChEC-seq

Chromatin endogenous cleavage (ChEC) uses fusion of a protein of interest to micrococcal nuclease (MNase) to target calcium-dependent cleavage to specific genomic loci in vivo. Here we report the combination of ChEC with high-throughput sequencing (ChEC-seq) to determine genomic occupancy of the generalist transcription factor Nsi1 and the catalytic subunit of the SWI/SNF chromatin remodelling complex Snf2 in the opportunistic yeast Candida albicans. Time-based analysis of ChEC-seq data reveals two classes of sites for each transcriptional regulator, one exhibiting rapid cleavage during the first 5 min with robust consensus motifs and the second showing slow cleavage at largely unique sites with low-scoring motifs. The ChEC-seq procedure described here will allow a high-resolution genomic location definition which will enable a better understanding of transcriptional regulatory circuits that govern fungal fitness and drug resistance in these medically important fungi. We adapted ChEC to a genome-wide sequencing readout (ChEC-seq) described in S. cerevisae to map the genome-wide distributions of the C. albicans transcription factors Snf2 and Nsi1 without the limitations associated with ChIP-based methods.