Zygotic genome activation during the maternal-to-zygotic transition

Annu Rev Cell Dev Biol. 2014:30:581-613. doi: 10.1146/annurev-cellbio-100913-013027. Epub 2014 Aug 11.


Embryogenesis depends on a highly coordinated cascade of genetically encoded events. In animals, maternal factors contributed by the egg cytoplasm initially control development, whereas the zygotic nuclear genome is quiescent. Subsequently, the genome is activated, embryonic gene products are mobilized, and maternal factors are cleared. This transfer of developmental control is called the maternal-to-zygotic transition (MZT). In this review, we discuss recent advances toward understanding the scope, timing, and mechanisms that underlie zygotic genome activation at the MZT in animals. We describe high-throughput techniques to measure the embryonic transcriptome and explore how regulation of the cell cycle, chromatin, and transcription factors together elicits specific patterns of embryonic gene expression. Finally, we illustrate the interplay between zygotic transcription and maternal clearance and show how these two activities combine to reprogram two terminally differentiated gametes into a totipotent embryo.

Keywords: cellular reprogramming; embryogenesis; maternal clearance; pioneer factors; pluripotency.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Cell Cycle
  • Chromatin / genetics
  • Chromatin / ultrastructure
  • Drosophila Proteins / physiology
  • Egg Proteins / genetics
  • Embryo, Nonmammalian
  • Embryonic Development / genetics*
  • Female
  • Gene Expression Regulation, Developmental* / drug effects
  • High-Throughput Nucleotide Sequencing
  • Histones / physiology
  • Humans
  • Models, Genetic
  • Oocytes / metabolism
  • Pregnancy
  • RNA Stability
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • RNA, Messenger, Stored / genetics*
  • Transcription Factors / genetics
  • Transcription, Genetic* / drug effects
  • Transcriptome
  • Xenopus Proteins / physiology
  • Zebrafish Proteins / physiology
  • Zygote / metabolism*


  • Chromatin
  • Drosophila Proteins
  • Egg Proteins
  • Histones
  • RNA, Messenger
  • RNA, Messenger, Stored
  • Transcription Factors
  • Xenopus Proteins
  • Zebrafish Proteins