The present invention provides replicating [100K-] adenovirus vectors that have an impairment in 100K activity. In particular preferred embodiments, the impairment is the result of a deletion in the 100K coding region of the adenovirus vector genome. It is further preferred that the adenovirus produces the E1 gene products. In an alternate embodiment, the adenovirus produces the E1a gene products, but has an impairment in the E1b coding region, such that replication of the virus is limited to p53- cells. Also described are methods of making and administering the inventive adenovirus vectors to a cell or to a subject. Further provided is use of the inventive [100K-] Ad vectors as a helper virus for the production of vector stocks of adeno-associated virus.