When you sell written content to a movie studio, they become the “author.” So unless your lawyer and reps manage to carve out some sort of legal proviso whereby you retain at least a portion of rights to the story’s characters, the quick answer is “no.” That said, you can always choose to retain the rights to your story… and refuse to move forward with any deal unless you retain rights to the underlying characters.

Note: This from someone who is *not* a lawyer. Best to direct the question to someone who is before making your own deals.