Baked Penne with Italian Sausage

12 ounces package dry penne pasta
1 pound mild Italian sausage
1 cup chopped onion
1/2 cup white wine
2 teaspoons olive oil
15 ounces tomato sauce
14 1/2 ounces diced tomatoes with garlic
6 ounces tomato paste
2 cups shredded Mozzarella cheese
Preheat oven to 350 degrees F (175 degrees C). Bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
Place sausage and onion in a large, deep skillet. Cook over medium high heat until evenly brown. Drain excess fat. Pour in wine, and cook for 1 minute, stirring, to deglaze the pan. Stir in tomato sauce, diced tomatoes and tomato paste. Simmer for 10 minutes, stirring occasionally. Toss with cooked pasta, and place in a 9x13 inch baking dish. Sprinkle top with mozzarella.
Bake in preheated oven for 20 minutes, or until cheese is melted.