The emerging role of transcriptional regulation in the oocyte-to-zygote transition

Fertilization marks the beginning of a new life by converting two terminally differentiated gametes into a single totipotent zygote. Central to this transition is a complex biological program commonly referred to as oocyte activation—an umbrella term for a series of profound changes that prepare the fertilized oocyte for totipotency [1, 2]. These include, among others, the completion of meiosis, the formation of the two pronuclei, and the selective translation of maternal RNAs. A remarkable aspect of oocyte activation is that it occurs in the absence of transcription. Not surprisingly, most of our knowledge of this process is centered on the posttranscriptional regulation of gene expression [3]. Yet, a recent body of evidence has brought new focus on the fundamental importance of transcriptional regulation during oogenesis as a primer for the oocyte-to-zygote transition [4].Fundacão para a Ciência e Tecnologia: PNC: PTDC/MEC-AND/30221/ 2017; RGM: PTDC/BEX-BID/0395/2014; PTDC/ BIA-BID/28441/2017; UID/BIM/04773/2013 CBMR 1334