Former  secretary of state Hillary Rodham Clinton and her husband, former president Bill Clinton, on  Jan. 1, 2014. (Jason Szenes/EPA)

The Democratic super PAC positioning itself to be the big-money advertising vehicle to back Hillary Rodham Clinton if she runs in 2016 announced a new board Thursday with strong ties to both labor and corporate interests.

Priorities USA Action, which backed President Obama’s reelection in 2012, is reconfiguring itself as a pro-Clinton group in advance of the next White House race. Obama’s former campaign manager, Jim Messina, and former Michigan governor Jennifer Granholm will serve as co-chairs, the super PAC announced Thursday.

Priorities will be led by an expanded 14-member board that represents many of the biggest interest groups in the Democratic Party, including labor unions, women’s groups and gay rights activists. The new members include Stephanie Schriock of EMILY’s List, former Human Rights Campaign president Joe Solomonese, Randi Weingarten of the American Federation of Teachers and William P. Hite of the labor group United Association.

Several of the new members also have close ties to major corporations, such as lawyer and longtime Democratic adviser Charles A. Baker III, a founding partner of the public affairs firm Dewey Square Group; former Clinton White House official Maria Echeveste, who co-founded Nueva Vista Group, a public policy and lobbying shop; and Viacom executive Marva Smalls. In addition, Jonathan Mantz, a principal at the lobbying firm BGR Group, is serving as a senior finance adviser to Priorities. And Solomonese now runs a corporate restructuring and public affairs firm.

Their relationships could open up lucrative new sources of funds for Priorities.

The relaunch of the super PAC comes after months of behind-the-scenes talks with other operatives who have  jumped into the effort on behalf of Clinton, who maintains that she had not decided whether to run. The first on the scene was the start-up Ready for Hillary, which has positioned itself as the organizer of the grass roots. Its quick ascendancy irritated some Clinton hands.

But the newly configured Priorities board indicates that the various groups are now working in close collaboration with each other, as well as with other major players in the Democratic infrastructure. Allida Black of Ready for Hillary has a seat on the board, as does David Brock, whose Correct the Record project is serving as a rapid response operation for 2016. Greg Speed, president of America Votes, a nonprofit that works closely with liberal advocacy groups around the country, is also a board member.

The robust cross-section of Democratic players and interest groups illustrates how forces within the party are increasingly coalescing around Clinton as the likely nominee. The decision by Messina, in particular, indicates a strong movement among former top Obama officials to Clinton’s camp, even though Vice President  Biden has not ruled out a run.