Phosphorylation of hRad17 by atr is Required for Cell Cycle Checkpoint Activation
Abstract
Targeted protein phosphorylation is a key event that serves to transduce DNA damage- induced cell signals from upstream sensors to downstream effectors. ATR kinase phosphorylates BRCA1 and Rad17 upon DNA damage. As a first approach to evaluate the functional consequence of IR-induced site-specifically phosphorylated residues on BRCA1, -we have established a BRCA1-dependent transcription-based assay which assesses the BRCA1-dependent repression function of ZBRK1 in mammalian cell from a reporter template bearing ZBRK1 DNA-binding sites. I found that ZBRK1 formed a homo-tetramer on the target gene promoter functioning as a DNA-binding dependent repressor as well as a DNA-binding independent corepressor. Functional dissection of ZBRK1 led to identification and characterization of a novel BRCA1-dependent repression domain encompassing ZBRK1 zinc fingers 5-8 and the unique C-terminus. This C-terminal repression domain functions in a BRCA1-dependent, histone deactylase-dependent and promoter-specific manner. Significantly, BRCA1 mediates ZBRK1 transcriptional repression function by modulating- two properties of ZBRK1 as a transcription factor: its DNA-binding and the recruitment of other co-repressor proteins. BRCA1-dependent ZBRK1 repression assay may now be' exploited to evaluate the influence of IR-induced site-specific phosphorylation of BRCA1 on its sequence-specific co-repressor function.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2005
- Accession Number
- ADA436963
Entities
People
- Wei Tan
Organizations
- University of Texas Health Science Center at San Antonio