Histone titration against the genome sets the DNA-to-cytoplasm threshold for the Xenopus midblastula transition.

ABSTRACT: During early development, animal embryos depend on maternally deposited RNA until zygotic genes become transcriptionally active. Before this maternal-to-zygotic transition, many species execute rapid and synchronous cell divisions without growth phases or cell cycle checkpoints. The coordinated onset of transcription, cell cycle lengthening, and cell cycle checkpoints comprise the midblastula transition (MBT). A long-standing model in the frog, Xenopus laevis, posits that MBT timing is controlled by a maternally loaded inhibitory factor that is titrated against the exponentially increasing amount of DNA. To identify MBT regulators, we developed an assay using Xenopus egg extract that recapitulates the activation of transcription only above the DNA-to-cytoplasm ratio found in embryos at the

SUBMITTER: Amodeo AA 

PROVIDER: S-EPMC4364222 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature