Disclosed are materials and methods for treating diseases of the
mammalian eye, and in particular, Usher syndrome 1B (USH1B). The invention provides AAV-based, dual-vector systems that facilitate the expression of full-length proteins whose coding sequences exceed that of the
polynucleotide packaging capacity of an individual AAV vector. In one embodiment, vector systems are provided that include i) a first AAV vector
polynucleotide that includes an
inverted terminal repeat at each end of the
polynucleotide and a suitable
promoter followed by a partial coding sequence that encodes an N-terminal portion of a full-length polypeptide; and ii) a second AAV vector polynucleotide that includes an
inverted terminal repeat at each end of the polynucleotide and a partial coding sequence that encodes a C-terminal portion of a full-length polypeptide, optionally followed by a
polyadenylation (pA)
signal sequence. In another embodiment, the
vector system includes i) a first AAV vector polynucleotide comprising an
inverted terminal repeat at each end, a suitable
promoter followed by a partial coding sequence that encodes an N-terminal portion of a full-length polypeptide followed by a
splice donor site and
intron and ii) a second AAV vector polynucleotide comprising an inverted terminal repeat at each end, followed by an
intron and a splice-
acceptor site for the
intron, followed by a partial coding sequence that encodes a C-terminal portion of a full-length polypeptide, optionally followed by a
polyadenylation (pA)
signal sequence. The coding sequence or the intron sequence in the first and second AAV vectors preferably includes a sequence region that overlaps.