NEW YORK (Reuters) - Hip hop mogul 50 Cent, Universal Music Group and several of its record labels were sued on Wednesday for promoting a "gangsta lifestyle" by a 14-year-old boy who says friends of the rapper assaulted him.

The lawsuit filed by James Rosemond and his mother, Cynthia Reed, says Universal Music Group -- owned by Vivendi SA -- and its labels Interscope Records, G-Unit Records and Shady Records, bear responsibility for the assault because they encourage artists to pursue violent, criminal lifestyles.

The lawsuit also names 50 Cent -- whose real name is Curtis Jackson -- Violator Management, Violator CEO Chris Lighty, Tony Yayo, a rapper and a member of 50 Cent's G-Unit hip hop group, and Lowell Fletcher, an employee of Yayo.

All defendants declined to comment.

Rosemond says he was assaulted on a Manhattan sidewalk in March 2007 by four men including Yayo and Fletcher.

The lawsuit claims Rosemond was targeted because he was wearing a T-shirt by Czar Entertainment, a management company that represents The Game. The Game is a former G-Unit rapper who fell out with the group and had become a rival rapper.

In February, Yayo, whose real name is Marvin Bernard, pleaded guilty to harassment and was sentenced to ten days of community service. Fletcher pleaded guilty to endangering the welfare of a child and was sentenced to 9 months in jail.

"The members of G-Unit, including defendants Yayo and 50 Cent, encouraged, sanctioned, approved and condoned its members threatening violence, and or engaging in violent acts in furtherance of its business," the lawsuit said.

The attack on Rosemond was intended to "promote and maintain Yayo and 50 Cent's 'gangsta' image," which was "promoted, marketed and advertised" by record labels.