JENNIFER LOPEZ HAS A LOT riding on "Selena." As star of the biopic about slain Tex-Mex music star Selena Quintanilla Perez, which opens next week, Lopez portrays an icon to millions of Latinos in the U.S. and abroad.

Selena, shot to death two years ago in Texas by a former employe, was in the midst of recording an Englishlanguage album that figured to make her the next big crossover artist.

Not only are legions of Selena fans depending on Lopez to do their idol justice, but Hollywood is watching, too.

With its subject, all-Latino cast and Latino director (Gregory Nava), the $18 million "Selena" is primed to open doors to more Latino-themed projects if it performs well at the box office.

"That's the whole idea of the movie so that Latinos can make a difference," says Lopez, flashing her million-dollar smile appropriately enough, after her $1 million "Selena" paycheck in a midtown restaurant recently.

"I feel there's lots of focus on Latino actresses and actors coming up right now, and because our community needs role models and people to look up to, I feel that responsibility."

Although Lopez has co-starred with some of Hollywood's biggest leading men in her short film career, "Selena" will be the first time she's basically carrying a movie on her own.

Lopez also realizes this is the role that could elevate her from playing sexy second bananas to the likes of Wesley Snipes and Woody Harrelson (1995's "Money Train"), Robin Williams (last year's "Jack") and Jack Nicholson ("Blood and Wine," released last month).

"It's scary. People are just getting to know my name now, even though I've been doing this for a long time," says Lopez, 26, who got her start in 1990 as a dancer on TV's "In Living Color."

"But with 'Selena,' my name became more known because of all the publicity when I got the role."

Landing it didn't come easy. In a nationwide talent search last year that reeked of publicity stunt, Nava and the "Selena" producers held an open casting call to fill the roles of Selena as an adult and child.

Thousands of hopefuls showed up, along with hordes of press. But when Lopez, whose first film was 1995's "My Family/Mi Familia" which Nava directed got the part, many felt she had it all along. "Which is totally wrong," says Lopez, who claims she had to audition and was left hanging for more than two months."There was a lot of controversy, but Greg [Nava] and Abraham [Quintanilla, Selena's father] were adamant about finding the right person."

Says Abraham Quintanilla (played by Edward James Olmos in the film): "I saw a lot of little things in her hand gestures, head movements, the way she talked that were similar to Selena." (In the film, Lopez lip-syncs to Selena's hits.)

Having the Quintanilla family's blessing was important to Lopez, a Bronx-bred Puerto Rican whose anointment met resistance from the Mexican-American community.

"It was really important that the family felt comfortable during the shooting," says Lopez. "They had free reign on the set. To us, it was as if it were their movie."

While her roles to date have been playing Latinas she was Nicholson's Cuban mistress in "Blood and Wine" Lopez looks forward to the day she's cast simply for her acting ability.

"I'm an actress, I'm Latina, take it however you want. But the great thing will be when it doesn't have to be a Latina. That means I'm an actress with box-office potential that people come to see. That's what Latinos in Hollywood should be striving for."