Investigation of the Causes of Breast Cancer at the Cellular Level: Isolation of In Vivo Binding Sites of the Human Origin Recognition Complex
Abstract
We study the process of DNA replication in proliferating human cells. Our efforts are directed to the identification and characterization of proteins that promote DNA replication ("initiators") as well as the DNA sequences recognized by them ("replicators") . We have focused in a group of initiator proteins called Origin Recognition Complex (ORC), Cdc6, and the Mini-Chromosome Maintenance (MCM) proteins. hOrclp, the largest subunit of ORC, appears to be a critical factor for the coordination of DNA replication with the cell division cycle. hOrclp levels are higher between the exit of mitosis and the end of Cl, the stage at which initiator proteins are assembled at the origins of replication. As cells enter S phase, hOrclp is polyubiquitinated on chromatin and degraded by the proteasome. hOrclp destruction is signaled in part by the SCFskP2 ubiquitin conjugating machinery. The controlled destruction of hOrclp likely contributes to avoid DNA overreplication, a common phenomenon in cancer cells. Our efforts to identify DNA replicator sequences using chromatin immunoprecipitation (ChIP) assays support the hypothesis that human origins of replication may not be defined by short specific DNA sequences but rather by higher-order chromatin structures.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2002
- Accession Number
- ADA409474
Entities
People
- Bruce Stillman
- Juan Mendez
Organizations
- Cold Spring Harbor Laboratory