As a model for human disease, mice lacking a copy of the Rb tumor suppressor are a distinct failure. For starters, they don't get retinoblastoma. Even patches of eye cells that lack both copies of Rb don't become tumors.
Tyler Jacks (Massachusetts Institute of Technology, Cambridge, MA) wondered if the Rb-related proteins p107 and p130 were filling in for Rb. This was consistent with the work of Anton Berns (Netherlands Cancer Institute, Amsterdam, Netherlands), who showed that mice lacking both Rb and p107 developed retinoblastomas. Perhaps the mouse versions of p107 and p130 were better than the human versions when it came to filling in for Rb and acting as tumor suppressors.
But Jacks' recent experiments suggest another solution. When Jacks eliminated Rb abruptly in adult mice, using an inducible recombinase to flip the gene out of the chromosome, the mice rapidly developed retinoblastomas. Thus,...
