biostudies-literatureTreen NNHGRINHGRI NIH HHSNINDS NIH HHSNIH1150-1156.e4https://www.ebi.ac.uk/biostudies/studies/S-EPMC5996753biostudies-literatureUnknown28(7)Most animal embryos display a delay in the activation of zygotic transcription during early embryogenesis [1]. This process is thought to help coordinate rapid increases in cell number during early development [2]. The timing of zygotic genome activation (ZGA) during the maternal-to-zygotic transition (MZT) remains uncertain despite extensive efforts. We explore ZGA in the simple protovertebrate, Ciona intestinalis. Single-cell RNA sequencing (RNA-seq) assays identified Cyclin B3 (Ccnb3) as a putative mediator of ZGA. Maternal Ccnb3 transcripts rapidly diminish in abundance during the onset of zygotic transcription at the 8-cell and 16-cell stages. Disruption of Ccnb3 activity results in precocious activation of zygotic transcription, while overexpression abolishes normal activation. TheseCurrent biology : CBDepletion of Maternal Cyclin B3 Contributes to Zygotic Genome Activation in the Ciona Embryo.PMC5996753NS076542T32HG003284T32 HG003284R01 NS076542Levine MHeist TWang WTreen NfalseDepletion of Maternal Cyclin B3 Contributes to Zygotic Genome Activation in the Ciona Embryo.Most animal embryos display a delay in the activation of zygotic transcription during early embryogenesis [1]. This process is thought to help coordinate rapid increases in cell number during early development [2]. The timing of zygotic genome activation (ZGA) during the maternal-to-zygotic transition (MZT) remains uncertain despite extensive efforts. We explore ZGA in the simple protovertebrate, Ciona intestinalis. Single-cell RNA sequencing (RNA-seq) assays identified Cyclin B3 (Ccnb3) as a putative mediator of ZGA. Maternal Ccnb3 transcripts rapidly diminish in abundance during the onset of zygotic transcription at the 8-cell and 16-cell stages. Disruption of Ccnb3 activity results in precocious activation of zygotic transcription, while overexpression abolishes normal activation. These2018-01-01T00:00:00Z2018 Apr2025-04-03T22:20:42.115Z2019-08-04T08:11:39ZS-EPMC59967532957647710.1016/j.cub.2018.02.046