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Dev Cell January 1, 2017; 42 (1): 82-96.e3.

Chk1 Inhibition of the Replication Factor Drf1 Guarantees Cell-Cycle Elongation at the Xenopus laevis Mid-blastula Transition.

Collart C , Smith JC , Zegerman P .

The early cell divisions of many metazoan embryos are rapid and occur in the near absence of transcription. At the mid-blastula transition (MBT), the cell cycle elongates and several processes become established including the onset of bulk transcription and cell-cycle checkpoints. How these events are timed and coordinated is poorly understood. Here we show in Xenopus laevis that developmental activation of the checkpoint kinase Chk1 at the MBT results in the SCFβ-TRCP-dependent degradation of a limiting replication initiation factor Drf1. Inhibition of Drf1 is the primary mechanism by which Chk1 blocks cell-cycle progression in the early embryo and is an essential function of Chk1 at the blastula-to-gastrula stage of development. This study defines the downregulation of Drf1 as an important mechanism to coordinate the lengthening of the cell cycle and subsequent developmental processes.

PubMed ID: 28697335
PMC ID: PMC5505860
Article link: Dev Cell
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: btrc cdc6 cdk1 chek1 dbf4 dbf4b diaph1 myc recql4 ticrr topbp1
Morpholinos: btrc MO1 cdc6 MO1 cdc6 MO2 dbf4 MO2 dbf4b MO1

Article Images: [+] show captions
References [+] :
Bartek, Checking on DNA damage in S phase. 2004, Pubmed