Senate Majority Leader Joseph Bruno, who has run the Republican chamber for more than a dozen years, made an announcement on Monday saying that he will not seek re-election in the fall.

Bruno, 79, of upstate Rensselaer County, considered the oldest serving state legislative leader in the country, has been the state’s top Republican since 2006.

He lost his wife, 57 years old Boby, in January, and is under federal investigation due to his outside business interests.

Bruno, who was treated for prostate cancer a few years ago, steps down at a time when the GOP has been incisively resisting in keeping control of the state Senate, where it has a 32-30 edge, with the Democrats control the Assembly.

Many older senators have stayed in, in large part, because of Bruno, who has been Senate majority leader since 1995. He leaving could change that, which would be a benefit to Democrats, who have picked up four seats in recent years.

A new majority leader will be voted on by the Senate Republicans who are scheduled to meet behind closed doors this morning in Albany.

Long Island Senator Dean Skelos is expected to be elected, with Senator Thomas Libous of Binghampton to be elected as deputy majority leader.

After the results come out, Bruno will step down and act as a rank-and-file member of the Senate.

If Skelos is chosen, as it seems more and more likely, it would strengthen the hold on state government by downstate, as every officeholder across the state, along with the Assembly speaker, lives either in Manhattan or Long Island. That could have a major effect on the struggle to set in motion the upstate economy.