Parmesan-Crusted Fish

2 tablespoons grated Parmesan cheese
1/3 cup plain low-fat yogurt
2 tablespoons prepared horseradish
2 tablespoons Dijon mustard
2 tablespoons lemon juice
1 teaspoon margarine, melted
8 (4 oz.) filets

Combine 1 tablespoon cheese and next 5 ingredients; spread evenly on 1 side of fish. Place fish, coated side up, on a rack coated with cooking spray; place rack in broiler pan and sprinkle with remaining cheese.