PARENT SESSION
1:30 PM to 3:30 PM
Monday, April 22, 2002
Poster Session 15 DNA Damage and Repair II
Room: Nevada Exhibition Center

(P20-220) Interaction of BCCIP with PCNA and transcription factors.

Meng, Xiangbing^*,1, Shen, Zhiyuan¹, ¹ Dept. of Molecular Genetics and Microbiology, Albuquerque, NM

ABSTRACT-
The BCCIP protein was identified as a BRCA2 and Cip1/p21 Interacting Protein (Liu, J., Yuan, Y., Huan, J., and Shen, Z. 2001. Oncogene, 20:336-35.). These interactions suggest a role of BCCIP in DNA damage response. It has been reported that BRCA2 co-localizes with proliferating cell nuclear antigen (PCNA) when replication was blocked by hydroxylurea treatment. In this study, we have found that the interaction between BCCIP and BRCA2 is enhanced by replication blockage with hydroxylurea. Using a yeast two hybrid screen, we have identified an interaction between BCCIP and the PCNA. This interaction was confirmed by co-immunoprecipitation of endogenous BCCIP with PCNA. These results suggest a role of BCCIP in the resolution of blocked replication forks in association with BRCA2. Detailed characterization of PCNA/BCCIP interaction will be presented. The potential post-translational modification of BCCIP in response to replication blockage that may regulate the BCCIP/BRCA2 interaction will be discussed. In addition, we have also found that the N-terminus domain of BCCIP activates transcription, and BCCIP co-precipitates with transcription factors TFIIH (XP-B) and RNA polymerase II. This result suggests an additional role of BCCIP in transcription regulation, or transcription coupled DNA repair process.

KEYWORDS: BRCA2, PCNA, BCCIP, p21