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Updated: Aug 30, 2026

Two- and Three-Dimensional Live Cell Imaging of DNA Damage Response Proteins
Published on: September 28, 2012
Active localization of the retinoblastoma protein in chromatin and its response to S phase DNA damage
Dror Avni1, Hong Yang, Fabio Martelli
1Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA.
Abstract:
The Rb protein suppresses development of an abnormal state of endoreduplication arising after S phase DNA damage. In diploid, S phase cells, the activity of protein phosphatase 2A (PP2A) licenses the stable association of un(der)phosphorylated Rb with chromatin. After damage, chromatin-associated pRb is attracted to certain chromosomal replication initiation sites in the order in which they normally fire. Like S phase DNA damage in Rb(-/-) cells, specific interruption of PP2A function in irradiated, S phase wt cells also elicited a state of endoreduplication. Thus, PP2A normally licenses the recruitment of Rb to chromatin sites in S phase from which, after DNA damage, it relocalizes to selected replication control sites and suppresses abnormal, postdamage rereplicative activity.
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