Related Experiment Videos
DNA-replication checkpoint control at the Drosophila midblastula transition
O C Sibon1, V A Stevenson, W E Theurkauf
1Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, 11794-5215, USA.
Nature
|July 3, 1997
Summary
Mutations in the grapes (grp) gene disrupt key developmental transitions in Drosophila embryogenesis. This study reveals grp
Area of Science:
- Developmental Biology
- Cell Cycle Regulation
- Genetics
Background:
- Embryogenesis begins with rapid, maternally controlled cell divisions.
- The midblastula transition (MBT) marks a shift to zygotic control, involving cell cycle elongation and gene transcription.
- The nucleocytoplasmic ratio is a key factor timing the MBT.
Purpose of the Study:
- To investigate the role of the grapes (grp) gene, a checkpoint 1 kinase homologue, in Drosophila embryogenesis.
- To understand how grp mutations affect the morphological and biochemical changes at the MBT.
- To elucidate the mechanism of cell-cycle control at the MBT.
Main Methods:
- Analysis of mutations in the Drosophila grapes (grp) gene.
- Observation of morphological and biochemical changes during embryogenesis.
- Investigation of DNA-replication checkpoint control and cell-cycle progression.
Main Results:
- grp mutations block MBT-associated morphological and biochemical changes.
- Mutations lead to a sustained maternal cell-cycle program.
- Checkpoint control of cell-cycle progression is disrupted in grp mutants.
- Evidence supports a model where nucleocytoplasmic ratio titration affects DNA replication and cell cycle delay.
Conclusions:
- The grapes (grp) gene is crucial for regulating the midblastula transition in Drosophila.
- Titration of maternal factors by nuclear material likely triggers MBT via cell-cycle delay.
- This delay facilitates S phase completion and the initiation of zygotic gene transcription.