Optimized CUT&Tag enables robust epigenome profiling in Schizosaccharomyces pombe

We optimized permeabilization for CUT&Tag in S. pombe, enabling robust H3K9me3 profiling using lightly fixed permeabilized sepheroplasts, overcoming limitations of ChIP-seq including crosslinking artifacts and high cell input. We established an optimized Cleavage Under Targets and Tagmentation (CUT&Tag) protocol for high-resolution epigenome profiling in Schizosaccharomyces pombe using Critical permeabilization refinements identified Lywallzyme as the optimal enzyme for spheroplast generation (>95 % efficiency in 60 min at 10 mg/mL), outperforming Zymolyase-20 T and combinatorial treatments. Systematic parameter optimization revealed concentration-dependent digestion kinetics and an inverse cell load-efficiency relationship (5 × 10⁵ cells achieving > 90 % conversion in 50 min at 5 mg/mL). Validated through H3K9me3 mapping in wild-type and clr4Δ strains (10⁶ cells/replicate), this approach captured specific heterochromatic enrichment at centromeres/telomeres with complete signal ablation in mutants, while reduced spike-in DNA (0.2 pg) significantly enhanced signal-to-noise ratios. The protocol enables robust epigenomic analysis with minimal cell input and enhanced resolution.