title: Reprogramming the maternal zebrafish genome after fertilization to match the paternal methylation pattern.
abstract: Early vertebrate embryos must achieve totipotency and prepare for zygotic genome activation (ZGA). To understand this process, we determined the DNA methylation (DNAme) profiles of zebrafish gametes, embryos at different stages, and somatic muscle and compared them to gene activity and histone modifications. Sperm chromatin patterns are virtually identical to those at ZGA. Unexpectedly, the DNA of many oocyte genes important for germline functions (i.e., piwil1) or early development (i.e., hox genes) is methylated, but the loci are demethylated during zygotic cleavage stages to precisely the state observed in sperm, even in parthenogenetic embryos lacking a replicating paternal genome. Furthermore, this cohort constitutes the genes and loci that acquire DNAme during development (i.e., ZGA to muscle). Finally, DNA methyltransferase inhibition experiments suggest that DNAme silences particular gene and chromatin cohorts at ZGA, preventing their precocious expression. Thus, zebrafish achieve a totipotent chromatin state at ZGA through paternal genome competency and maternal genome DNAme reprogramming.
authors.affiliation: Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
authors.forename: Magdalena E
authors.initials: ME
authors.lastname: Potok
authors.forename: David A
authors.initials: DA
authors.lastname: Nix
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Parnell
authors.forename: Bradley R
authors.initials: BR
authors.lastname: Cairns
mesh_terms: D000818:Animals; D019175:DNA Methylation; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D044127:Epigenesis, Genetic; D005260:Female; D005306:Fertilization; D008297:Male; D009865:Oocytes / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D015027:Zebrafish / Q000235:genetics*