COMPOSITIONS AND METHODS FOR TREATMENT OF ACHROMOTOPSIA

1 . A polynucleotide cassette for enhanced expression of a transgene in cone cells of a mammalian retina, comprising:

(a) a promoter region, wherein the promoter region is specific for retinal cone cells;

(b) an optimized 5′ untranslated terminal repeat (UTR) sequence to increase translation of CNGB3 protein;

and

(c) a polyadenylation site.

2 . The polynucleotide cassette of claim 1 , further comprising at least one recombinant adeno-associated virus serotype 2 (AAV2) inverted terminal repeat (ITR).

3 . The polynucleotide cassette of claim 2 , further comprising two AAV2 ITR wherein one ITR is 5′ to the promoter and one ITR is 3′ to the polyadenylation site.

4 . The polynucleotide cassette of claim 1 , wherein the promoter region comprises SEQ ID NO: 14 or SEQ ID NO: 15.

5 . The polynucleotide cassette of claim 4 , wherein the promoter further comprises a human opsin locus control region (LCR).

6 . The polynucleotide cassette of claim 5 , wherein the LCR comprises SEQ ID NO: 13.

7 . (canceled)

8 . The polynucleotide cassette of claim 1 , further comprising a unique coding sequence optimized for high level expression and low CpG operatively linked to the promoter region, wherein the coding sequence encodes a CNGB3 gene.

9 . The polynucleotide cassette of claim 8 , wherein the unique coding sequence is SEQ ID NO:10 or SEQ ID NO: 20, or a sequence having at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 97% identity thereto.

10 . (canceled)

11 . The polynucleotide cassette of claim 1 , wherein the polyadenylation site is SEQ ID NO: 22 or SEQ ID NO: 23.

12 . (canceled)

13 . A polynucleotide cassette comprising in 5′ to 3′ orientation:

(a) a first ITR comprising SEQ ID NO: 12;

(b) a human ops in locus control region comprising SEQ ID NO: 13;

(c) a promoter selected from SEQ ID NOs: 14 or 15;

(d) a chimeric intron comprising SEQ ID NO: 16;

(e) a 5′ UTR selected from comprising SEQ ID NOs: 17, 18 or 25;

(f) a 10 nt optimized lead sequence comprising SEQ ID NO:24;

(g) an optimized Kozak sequence comprising SEQ ID NO: 19;

(h) a nucleotide sequence encoding a therapeutic protein;

(i) a polyA encoding nucleotide sequence selected from a sequence comprising SEQ ID NOs: 22 or 23; and

(j) optionally, a second ITR comprising SEQ ID NO: 12;

wherein there is at least one ITR.

14 - 15 . (canceled)

16 . The polynucleotide cassette of claim 1 comprising SEQ ID NO: 3.

17 - 21 . (canceled)

22 . A recombinant virus comprising:

(a) a variant capsid protein; and

(b) the polynucleotide cassette of claim 1 .

23 . The recombinant virus of claim 22 , wherein the recombinant virus is a recombinant adeno associated virus (AAV).

24 . The recombinant virus of claim 23 , wherein the capsid protein is an AAV variant 7m8 capsid protein or is derived from the AAV variant 7m8 capsid protein.

25 . A pharmaceutical composition comprising the recombinant virus of claim 22 and a pharmaceutically acceptable excipient.

26 . A method of treating achromotopsia in a human subject in need thereof, the method comprising administering to the subject the recombinant adeno-associated virus (rAAV) at a dosage ranging from about 1×10 9 to about 1×10 14 vector genomes (vg)/eye, wherein the rAAV comprises a CNGB3 gene, and wherein the rAAV comprises an AAV2 capsid variant that transduces foveal cone photoreceptors.

27 . The method of claim 26 , wherein the administration is selected from intravitreal (IVT) injection, subretinal (SR) injection, intraocular injection, or suprachoroidal injection.

28 - 38 . (canceled)

39 . An isolated host cell transfected or transduced with the polynucleotide cassette of claim 1 .