DOT1L regulates chromatin reorganization and gene expression during sperm differentiation

EMBO Rep. 2023 Jun 5;24(6):e56316. doi: 10.15252/embr.202256316. Epub 2023 Apr 26.


Spermatozoa have a unique genome organization. Their chromatin is almost completely devoid of histones and is formed instead of protamines, which confer a high level of compaction and preserve paternal genome integrity until fertilization. Histone-to-protamine transition takes place in spermatids and is indispensable for the production of functional sperm. Here, we show that the H3K79-methyltransferase DOT1L controls spermatid chromatin remodeling and subsequent reorganization and compaction of the spermatozoon genome. Using a mouse model in which Dot1l is knocked-out (KO) in postnatal male germ cells, we found that Dot1l-KO sperm chromatin is less compact and has an abnormal content, characterized by the presence of transition proteins, immature protamine 2 forms and a higher level of histones. Proteomic and transcriptomic analyses performed on spermatids reveal that Dot1l-KO modifies the chromatin prior to histone removal and leads to the deregulation of genes involved in flagellum formation and apoptosis during spermatid differentiation. As a consequence of these chromatin and gene expression defects, Dot1l-KO spermatozoa have less compact heads and are less motile, which results in impaired fertility.

Keywords: H3K79 methylation; flagellum development; gene regulation; histone-to-protamine transition; spermatogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / genetics
  • Chromatin Assembly and Disassembly
  • Chromatin* / genetics
  • Chromatin* / metabolism
  • Gene Expression
  • Histones* / metabolism
  • Male
  • Mice
  • Proteomics
  • Semen / metabolism
  • Spermatogenesis / genetics
  • Spermatozoa / metabolism


  • Chromatin
  • Histones
  • Dot1l protein, mouse