Staten Island District Attorney Dan Donovan kicked off his bid for attorney general Sunday - and grabbed a quick endorsement from Mayor Bloomberg, who was at his side. Donovan, 53, becomes the first Republican to enter the race beside a crowded field of Democrats vying for the chance to be the state's top prosecutor. "We have worked very closely together on making the safest big city in the nation even safer," Bloomberg said, noting Donovan's efforts to crack down on illegal guns and sex offenders. Donovan is a lifetime New Yorker: He's a Staten Island native who attended St. John's University and Fordham Law School.