Depletion of Maternal Cyclin B3 Contributes to Zygotic Genome Activation in the Ciona Embryo
Overview
Affiliations
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. These observations suggest that the depletion of maternal Cyclin B3 products is a critical component of the MZT and ZGA. We discuss evidence that this mechanism might play a conserved role in the MZT of other metazoans, including mice and humans.
The maternal-to-zygotic transition: reprogramming of the cytoplasm and nucleus.
Kojima M, Hoppe C, Giraldez A Nat Rev Genet. 2024; .
PMID: 39587307 DOI: 10.1038/s41576-024-00792-0.
Physical modeling of embryonic transcriptomes identifies collective modes of gene expression.
Skinner D, Lemaire P, Mani M bioRxiv. 2024; .
PMID: 39131269 PMC: 11312445. DOI: 10.1101/2024.07.26.605398.
Meiotic Cell Cycle Progression in Mouse Oocytes: Role of Cyclins.
Kim H, Kang M, Seong S, Jo J, Kim M, Shin E Int J Mol Sci. 2023; 24(17).
PMID: 37686466 PMC: 10487953. DOI: 10.3390/ijms241713659.
Marine Invertebrates One Cell at A Time: Insights from Single-Cell Analysis.
Bump P, Lubeck L Integr Comp Biol. 2023; 63(5):999-1009.
PMID: 37188638 PMC: 10714908. DOI: 10.1093/icb/icad034.
An FGF timer for zygotic genome activation.
Treen N, Chavarria E, Weaver C, Brangwynne C, Levine M Genes Dev. 2023; 37(3-4):80-85.
PMID: 36801820 PMC: 10069452. DOI: 10.1101/gad.350164.122.