SAN FRANCISCO -- Internet infrastructure company VeriSign announced on Tuesday it had sold its minority share in a mobile entertainment joint venture to Rupert Murdoch's News Corp. for $200 million.

The Mountain View, California-based company said it was selling its stake in the joint venture, Jamba, a creator of mobile content such as ringtones, to concentrate on its main business of providing Internet infrastructure services.

The joint venture was created in 2007 when News Corp. acquired a controlling interest in VeriSign's wholly owned Jamba subsidiary for $188 million and combined it with the Fox Mobile Entertainment unit.

"This sale is an important step in our effort to focus on our core businesses in Internet infrastructure," VeriSign interim chief executive Jim Bidzos said in a statement.

"News Corp. has been a good business partner and we wish them well as they continue to operate an exciting mobile entertainment business," he said.

VeriSign, which had revenue of 1.5 billion dollars in 2007, operates the largest domain name registry in the world, managing .com, .net, .cc, and .tv domain names.

News Corp.'s empire includes television stations, newspapers, Hollywood film studios, book publishers and the social networking site MySpace.