Ameren Corp. on Wednesday announced a reshuffling of several senior officers. The St. Louis-based company also said Karen Foss, the company's senior vice president of communications and brand management, will retire.

Thomas Voss, Ameren's CEO, said the following moves are effective March 2:

• Charles D. Naslund will become senior vice president of generation and environmental projects for Ameren Missouri. He had been CEO of Ameren Energy Resources Co.;

• Steven R. Sullivan, formerly Ameren's general counsel, will take over as head of Ameren Energy Resources, the company's merchant generating unit;

• Gregory L. Nelson will take Sullivan's place as vice president and general counsel.

Foss, a well-known news anchor for 25 years at KSDK in St. Louis, joined Ameren four years ago and was promoted to senior vice president in 2009.

She did most of her work for the utility off-camera, but did make an occasional cameo.

In 2007, Foss starred in an infomercial produced by Ameren to help repair the company's image in the wake the Taum Sauk disaster. Two years later, she appeared in television commercials to help build support for legislation that would pave the way for a second nuclear reactor in Callaway County.