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Updated: Jul 13, 2026

Studying RNA Interactors of Protein Kinase RNA-Activated during the Mammalian Cell Cycle
Published on: March 5, 2019
Activation of the DNA replication checkpoint through RNA synthesis by primase
W M Michael1, R Ott, E Fanning
1Department of Biology, University of California, San Diego, La Jolla, CA 92093-0349, USA. matt@mcb.harvard.edu
Abstract:
When DNA replication is inhibited during the synthesis (S) phase of the cell cycle, a signaling pathway (checkpoint) is activated that serves to prevent mitosis from initiating before completion of replication. This replication checkpoint acts by down-regulating the activity of the mitotic inducer cdc2-cyclin B. Here, we report the relation between chromatin structure and induction of the replication checkpoint. Chromatin was competent to initiate a checkpoint response only after the DNA was unwound and DNA polymerase alpha had been loaded. Checkpoint induction did not require new DNA synthesis on the unwound template strand but did require RNA primer synthesis by primase. These findings identify the RNA portion of the primer as an important component of the signal that activates the replication checkpoint.
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