Rep. Jan Schakowsky (Ill.) on Wednesday announced the support of the dean of the House and two others in her bid to become the vice chairwoman of the Democratic Caucus, while her leading rival, Rep. Joe Crowley (N.Y.), surpassed the 50-Member endorsement mark.

Schakowsky added to her backer list Reps. John Dingell (Mich.), Brad Sherman (Calif.) and Henry Waxman (Calif.).

The endorsement by Dingell, the longest-serving House Member and the ranking member on Energy and Commerce, came just hours before he was to be honored at a tribute ceremony by his friends and colleagues for his 50 years of service in the House.

“All three of these endorsements are a great boost to my campaign as we continue to gain numbers and move forward,” Schakowsky said in a statement. “I am deeply honored to have all three and expect that I will announce more supporters soon. I am particularly moved that, as he marks 50 years of service in Congress, the Dean of the House, John Dingell, has chosen to throw his support behind me.”

Schakowsky now has 46 public supporters, five fewer than Crowley’s 51. Crowley passed the 50-Member mark on Wednesday by adding two more names to his list, Reps. Charlie Melancon (La.) and Mike McIntyre (N.C.).

Rep. John Larson (Conn.) is the third candidate in the three-person race for vice chairman of the Caucus. Larson, who has said he doesn’t plan to campaign through the media, has laid out 18 public backers.

The vice chairman is the No. 4 leadership post for House Democrats and is now held by Rep. James Clyburn (S.C.). Clyburn is prevented from seeking a third term as vice chairman, and he has announced plans to seek the Caucus chairman position.

The election for the post is scheduled for late next year, but it could come as early as January if Democratic Sen. Jon Corzine (N.J.) wins the governorship on Nov. 8 and taps Caucus Chairman Bob Menendez (N.J.) to fill his seat.