SS18L2, a small protein of 77 amino acids and a member of the SNH-protein family, was newly described as an essential gene regulating cell cycle-related processes through epigenome-wide CRISPR/Cas9 library-mediated knockout screens. Cells knocked-out of SS18L2 were observed to arrest at the G2/M transition and showed aberrant mitotic spindle formation and cell size. Many genes regulating the cell cycle progression were observed to be downregulated upon knockout. I propose the application of multiple state-of-the-art techniques in novel set-ups to spatio-temporally resolve the mechanisms by which SS18L2 regulates cell cycle. The description of new chromatin regulation mechanisms and characterization of SS18L2 will be achieved through this project. The interactions uncovered by this study will bring chromatin regulation and cell cycle biology fields together. I aim to reveal a holistic perspective on the interplay between epigenetics and cell cycle regulation, demonstrating that these fields are interconnected rather than existing in mutually exclusive contexts.