Role of Brca1 in Nonhomologous DNA End Joining
Abstract
To examine the possible role of the breast cancer susceptibility factor BRCA1 in the nonhomologous end joining pathway of DNA double-strand break repair, an assay to detect both accurate and inaccurate end joining events in intact cells was devised. A fusion gene of green fluorescent protein (EGFP) and neomycin resistance (nec) was constructed with a linker containing cleavage sites for the enzymes BcgI and 1-Scel. EcgI induces two simultaneous breaks, excising a 34-bp segment of DNA. Accurate repair of such a break would be detected as a 34-bp deletion that would put neo back in-frame and confer G4l8 resistance. Inaccurate repair events of both BcgI- and 1-Scel-induced breaks would similarly be detected. A lentivirus vector was constructed to introduce the fusion gene into human cells, and transductants of MCF-7 breast tumor cells were isolated. Although development of the assay system is not yet complete, proof-of-principle experiments showed that deletions could indeed be generated by 1-Scel-induced cleavage and detected as reactivation of the neo gene. Intracellular DNA cleavage by BcgI, introduced into cells by electroporation was also demonstrated, although it remains to be determined whether such cleavage will be sufficient to detect repair and assess repair accuracy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2004
- Accession Number
- ADA429936
Entities
People
- Lawrence F. Povirk
Organizations
- Virginia Commonwealth University