WHO TESTIFIED: Christine Varney, head of the Justice Department's antitrust division, and Julius Genachowski, chairman of the Federal Communications Commission.

WHAT THEY SAID: The regulators pledged a rigorous government review of the proposed combination of Comcast Corp. and NBC Universal.

THE DEAL: Comcast, the nation's largest cable TV company, is seeking approval to acquire a 51 percent stake in NBC Universal from General Electric Co.