Some of the Upper Division Cluster courses are offered through my major department. Can I take these classes to fulfill my major requirement as well as my University Studies requirements?

No.  The Upper Division Cluster requirement can only be satisfied by classes taken outside a student's major program.  However, students who have chosen a minor or second major program may take Cluster classes within that department and use those credits to simultaneously satisfy both their Upper Division requirements and the requirements of the second major or minor program.