An unfolding breast cancer story

BRCA1 is one of the most intensely studied proteins in the history of cancer research, and it has more than its fair share of proposed protein partners and postulated activities. Rong Li hopes that he has made sense out of this mountain of information in a paper by Ye et al. starting on page 911. He and his coauthors suggest that BRCA1's effects on transcription and DNA repair have as their root cause a chromatin-unfolding activity of two BRCT repeats at the COOH terminus of the protein.

The assay for unfolding used here has been used with transcriptional activators. It involves targeting BRCA1 or a subset of the protein to multiple (probably several thousand) lacO repeats scattered over 90 Mb of heterochromatin. In 14% of cells expressing BRCA1 linked to the lac repressor there is...