The tumor suppressor candidate p33(ING1) mediates repair of UV-damaged DNA

The biological functions of the tumor suppressor, ING1, have been studied e xtensively in the last 5 Sears since it was cloned. It shares many biologic al functions with those of p53 and has been reported to mediate growth arre st, senescence, apoptosis, anchorage-dependent growth, and chemosensitivity , Some of these functions, such as cell cycle arrest and apoptosis, have be en shown to be dependent on the activity of both ING1 and p53 proteins. In this study, we report that p33(ING1) (one of ING1 isoforms) is also involve d in the modulation of DNA repair. We found that overexpression of p33(ING1 ) enhances repair of UV-damaged DNA and that p53 is required for the repair process. Furthermore, binding between ING1 and GADD45 has been detected. T hese observations suggest that p33(ING1) cooperates with p53 in nucleotide excision repair and that GADD45 mag be one of its components.