SAN FRANCISCO — Ronnie Lott and J.T. Snow helped put up a wall, Marshawn Lynch cleared space with a sledgehammer and the Pac-12 got started building the studios for its new television network. The conference held the groundbreaking for the Pac-12 networks in downtown San Francisco on Monday, about six months before it will hit the air with a national cable television network, six regional networks and a digital network. "It's truly a seminal moment for the conference," Commissioner Larry Scott said at a ceremony featuring former great athletes from the conference, as well as San Francisco Mayor Ed Lee.