Discovery and Development of Inhibitors that Selectively Interfere with Cyclin-Dependent Kinase Substrate Recognition
Abstract
The Origin Recognition Complex (ORC) is thought to function in the loading of replication proteins on the chromatin. In lower organisms, chromatin loading of ORC is required for replication, and thus, cell proliferation. In this funding period we report further progress on previous observations that low levels of Orc2 prevent activation of the Cyclin Dependent Kinase (CDK) cycle. By depleting Orc2 using siRNA, we showed that Cyclin E associated kinase activity was decreased. We have found that we can rescue this inhibition by depleting p27 and p21 along with Orc2. This restores CDK activity, and partially rescues BrDU incorporation. However, these rescued cells show increased apoptosis, indicating that the inhibition caused by Orc2 serves a protective role for the cells. We observed similar effects of low Orc2 levels on the CDK cycle in a stable cell line hypomorphic for Orc2. These cells show difficulty entering S-phase, and also have a Cyclin E associated kinase activity decrease. However, once these cells enter S-phase, cell cycle progression and replication fork firing appear to be normal. This indicates the primary role for Orc2 in mammalian cells may be activation of the CDK cycle.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2005
- Accession Number
- ADA442995
Entities
People
- Anindya Dutta
- Jamie Teer
Organizations
- Brigham and Women's Hospital