Cyclin D1 gene expression is essential for cell cycle progression from the maternal-to-zygotic transition during blastoderm development in Japanese quail

Embryogenesis proceeds by a highly regulated series of events. In animals, maternal factors that accumulate in the egg cytoplasm control cell cycle progression at initial stage cleavage. However, regulation is switched to system governed activated nuclear genome specific development, referred as maternal-to-zygotic transition (MZT). Detailed molecular analyses have been performed on and zygotic genes MZT mammals, fishes chicken; however, underlying mechanisms remain unclear quail. present study, we demonstrated occurred blastoderm V Japanese quail using novel gene targeting technology which CRISPR/Cas9 intracytoplasmic sperm injection (ICSI) systems were combined. At V, found retinoblastoma 1 (RB1) protein expression was down-regulated, whereas cyclin D1 (CCND1) initiated. When microinjection sgRNA containing CCND1-targeted sequencing Cas9 mRNA administered pronuclear stage, development stopped down-regulation RB1 did not occur. This result indicates most notable difference from mammals CCND-knockout embryos are capable developing beyond MZT. We also showed CCND1 induced phosphorylation serine/threonine residues protein, resulted degradation this protein. These results suggest one key for MZT, elimination may contribute after during Our technology, combined ICSI, has potential become powerful tool avian-targeted mutagenesis.