Comprehensive observation of histone lysine lactylation during gametogenesis of Drosophila melanogaster

Background: Histone post-translational modification (PTM) is an important epigenomic regulation content and an essential process regulating gene expression. Histone lysine lactylation is the newly identified histone PTM that utilizes the lactyl moiety for its modification. Although histone lysine lactylation is considered an essential outcome of the Wardburg effects and the interconnection between cellular metabolism and gene regulation, the developmental contexts involving this PTM are largely unknown. In this study, we comprehensively observed histone lysine lactylation during Drosophila oogenesis, one of the developmental contexts in which chromatin regulation plays crucial roles. Results: Our study revealed that lactylation on the specific histone lysine mainly occurs in the oocyte karyosome and condensed meiotic chromosome, suggesting histone lysine lactylation has a vital role in female meiosis. Interestingly, one of the histone lysine lactylations, lactylation of lysine 14 of histone H3, is intensively observed in the meiotic germline in the mouse ovary, suggesting that lactylation has an evolutionarily conserved role. Conclusions: Our results revealed that histone lysine lactylation is predominantly present in transcriptionally repressive meiotic chromatin, which contradicts the previously reported function of histone lactylation in transcriptional activation. This study, therefore, provides the first fundamental information to understand the role of histone lysine lactylation in the germline and repressive chromatin.