Identification of Histone Modifications Reveals a Role of H2b Monoubiquitination in Transcriptional Regulation of dmrt1 in Monopterus albus

Gonadal trans-differentiation from ovary to testis occurs in a same individual, suggesting a role of epigenetic regulation.However, histone modifications concerning the sex reversal process remain elusive.We analyzed histone modifications using liquid chromatography-tandem mass spectrometry (LC-MS/MS).Chromatin immunoprecipitation followed by sequencing (ChIP-seq) technology was used to test chromatin immunoprecipitation of gonads.Western blot analysis was performed to analyze protein expression.Immunofluorescence analysis was conducted to localize proteins in gonadal tissues.Here, we report a developmental atlas of histone modifications in the gonadal differentiation, including acetylation, methylation, and ubiquitination.We provided a detail distribution map of these modification sites including novel histone modifications along histones H2a, H2b, H3, and H4, and revealed their relationship with types of gonadal differentiation.We then determined a testis-enriched histone modification site, H2b monoubiquitination at K120, and its association with spermatogenesis.ChIP-seq demonstrated that the modification was highly enriched in the male sex-determining gene dmrt1 (doublesex and mab-3 related transcription factor 1), in particular, in its exon regions, suggesting its role in transcriptional regulation of dmrt1 in testis.Together, these data not only provide a new resource for epigenetic study in gonadal development, but also define an association of histone modifications with gonadal differentiation from ovary to testis.