Missouri state Auditor Tom Schweich appears ready to launch his expected 2016 campaign for governor.

If so, he will be the second well-known Republican to seek the job now held by Democrat Jay Nixon, who cannot seek re-election because of term limits.

Former House Speaker Catherine Hanaway declared her candidacy last year. The only announced Democrat is Missouri Attorney General Chris Koster.

Schweich’s campaign sent out a release late Tuesday saying only that he is making “a major announcement’’ at 4 p.m., Wednesday at the University of Missouri-St.Louis.

But several Republican activists have forwarded emails from top St. Louis County GOP leaders calling on supporters to show up at UMSL to cheer on Schweich as he makes his 2016 plans official.

Allies have encouraged Schweich to run for governor for more than a year, but he had declined to make any of his plans public until after his re-election in November.

A county native, Schweich has some prominent allies among the region’s top Republicans, including former U.S. Sen. John C. Danforth – a longtime mentor and former boss – and prominent donor and businessman Sam Fox.

Both were big boosters of Schweich when he made his first – and successful – bid for public office in 2010, when he ousted then-Auditor Susan Montee, a Democrat.

Schweich generally has attracted praise for his office’s performance and his vigilance in conducting dozens of audits of various state and local programs and officials. But he also has come under fire, from Democrats, over his legal challenges to some of Nixon's actions.

In any case, Missouri Democrats failed to put up a candidate to challenge Schweich in the November election for auditor.

Schweich also has been an outspoken critic of some fellow Republicans. His campaign has blasted Hanaway because the bulk of the campaign money she has raised so far has come from one man: wealthy financier Rex Sinquefield.