일시: 3/18(목) 16시
장소: 화상 세미나(zoom)로 진행 (https://ssu-ac-kr.zoom.us/j/85252651579)
강사: 임도환(숭실대학교 의생명시스템학부 교수)
제목: Initiation of parental genome reprogramming in fertilized oocyte by splicing kinase SRPK1
The paternal genome undergoes a massive exchange of histone with protamine for compaction into sperm during spermiogenesis. Upon fertilization, this process is potently reversed, which is essential for parental genome reprogramming and subsequent activation; however, it remains poorly understood how this fundamental process is initiated and regulated. Here, we report that the previously characterized splicing kinase SRPK1 initiates this life-beginning event by catalyzing sitespecific phosphorylation of protamine, thereby triggering protamine-to-histone exchange in the fertilized oocyte. Interestingly, protamine undergoes a DNA-dependent phase transition to gel-like condensates and SRPK1-mediated phosphorylation likely helps open up such structures to enhance protamine dismissal by nucleoplasmin (NPM2) and enable the recruitment of HIRA for H3.3 deposition. Remarkably, genome-wide assay for transposaseaccessible chromatin sequencing (ATAC-seq) analysis reveals that selective chromatin accessibility in both sperm and MII oocytes is largely erased in early pronuclei in a protamine phosphorylationdependent manner, suggesting that SRPK1-catalyzed phosphorylation initiates a highly synchronized reorganization program in both parental genomes.