II -infected rabbits to be dramatically lower than the proviral loads in rabbits exposed to ACH. Our data indicate selected mutations in pX ORF II diminish the ability of HTLV-1 to maintain high viral loads in vivo and suggest an important function for p13 II and p30 II in viral pathogenesis.

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The highly conserved coadapters CREB binding protein (CBP) and p300 form complexes with CREB as well as other DNA binding transcription factors to modulate chromatin remodeling and thus transcription. Human T-lymphotropic virus type 1 (HTLV-1) transcription is controlled, in part, by the CREB/ATF family of transcription factors which bind promoter sequences and function as complexes with the viral oncogenic protein Tax. We have reported that the nuclear localizing protein p30 II of HTLV-1 functions as a transcription factor, differentially modulates CREB-responsive promoters, and is critical for maintenance of proviral loads in rabbits. In this study, we tested whether p30 II directly interacts with CBP/p300 to modulate gene transcription. Gal4(BD)-p30II -mediated transactivation was enhanced following exogenous expression of p300 and was competitively repressed by the p300 binding protein, adenovirus E1A, and E1ACR2 (mutated for retinoblastoma binding but retaining p300 binding). In contrast, E1ACR1 (mutated for p300 binding) failed to alter Gal4(BD)-p30 II -mediated transactivation. In addition, Gal4(BD)-p30 II -mediated transactivation was competitively inhibited by the cotransfection of CMV-p30 II -HA and CMV-Tax but could be rescued by exogenous p300. Importantly, we demonstrate that p30 II colocalizes with p300 in cell nuclei and directly binds to CBP/p300 in cells. Deletion mutants of CBP/p300 were used to localize the site critical for binding p30 II to a highly conserved KIX region. DNA binding assays confirmed the interference of p30 II with the assembly of CREB-Tax-p300/CBP multiprotein complexes on 21-bp repeat oligonucleotides in vitro. Collectively, our results demonstrate that CBP/p300 is a cellular protein target for HTLV-1 p30 II and mediates its transcriptional effects in vivo.The coactivators CREB binding protein (CBP) and p300 mediate transcriptional control of various cellular and viral DNA binding transcription factors. These coactivators are highly similar in nucleotide sequence, are evolutionarily conserved, and are often referred to together as CBP/p300, despite evidence of divergent functions (10, 25). These proteins bridge transcription factors to relevant promoters, have intrinsic histone acetyltransferase (HAT) activity, and form complexes with proteins such as CBP/p300 binding protein-associated factor, which also exhibits HAT activity (26). Recent reviews provide a growing list of cellular and viral proteins that interact with either CBP or p300, including steroid and retinoid hormone receptors, CREB, c-Jun, c-Myb, Sap-1a, c-Fos, MyoD, p53, Stat-1/2, NF-B, pp90rsk , TATA-binding protein, and TFIIB (4, 25, 29, 30). Among viral regulatory proteins, human T-lymphotropic virus type 1 (HTLV-1) Tax, adenovirus E1A, Kaposi's sarcoma-associated herpesvirus viral interferon regulatory factor protein, and simian virus 40 large T antigen also target and affect CBP and p300 functions (1-3, 17, 32, 38, 41, 52).Complex retroviruses, like HTLV-1, must regulate their gene expression in cooperation...

Recombinant adeno-associated viruses are important vectors for retinal gene delivery. Currently utilized vectors have relatively slow onset and for efficient transduction it is necessary to deliver treatment subretinally, with the potential for damage to the retina. Amino-acid substitutions in the viral capsid improve efficiency in rodent eyes by evading host responses. As dogs are important large animal models for human retinitis pigmentosa, we evaluated the speed and efficiency of retinal transduction using capsid-mutant vectors injected both subretinally and intravitreally. We evaluated AAV serotypes 2 and 8 with amino-acid substitutions of surface exposed capsid tyrosine residues. The chicken beta-actin promoter was used to drive green fluorescent protein expression. Twelve normal adult beagles were injected, 4 dogs received intravitreal injections, 8 dogs received subretinal injections. Capsid-mutant viruses tested included AAV2(quad Y-F) (intravitreal and subretinal), and self-complementary scAAV8(Y733F) (subretinal only). Contralateral control eyes received injections of scAAV5 (subretinal) or scAAV2 (intravitreal). Subretinally delivered vectors had a faster expression onset than intravitreally delivered vectors. Subretinally delivered scAAV8(Y733F) had a faster onset of expression than scAAV5. All subretinally injected vector types transduced the outer retina with high efficiency, and the inner retina with moderate efficiency. Intravitreally delivered AAV2(quad Y-F) had a marginally higher efficiency of transduction of both outer retinal and inner retinal cells than scAAV2. Because of their rapid expression onset and efficient transduction, subretinally delivered capsid-mutant AAV8 vectors may increase the efficacy of gene therapy treatment for rapid photoreceptor degenerative diseases. With further refinement, capsid-mutant AAV2 vectors show promise for retinal gene delivery from an intravitreal approach.

A 1-year-old Shar Pei presented for recent-onset exophthalmos and right peri-ocular facial swelling. Physical examination revealed the facial mass was of soft-tissue consistency and nonpainful to the dog. Due to inability to retropulse the globe during ophthalmologic examination, it was suspected the mass had impinged into the orbit, resulting in rostral displacement of the globe. Anatomic location suggested the lesion was probably associated with the zygomatic salivary gland. Fine-needle aspiration and subsequent cytological evaluation of fluid extracted from the facial mass was consistent with a diagnosis of zygomatic mucocele. Computed tomography imaging confirmed a single fluid-filled mass was resulting in both the facial distention and the exophthalmos. A modified, lateral orbitotomy surgical approach was selected for excision of the lesion to provide ventral exposure to the orbit, while minimizing trauma to the globe and supporting structures. Histopathology of the excised lesion confirmed a diagnosis of zygomatic mucocele. This case demonstrates utilization of a modified lateral orbitotomy for effective surgical management of a zygomatic mucocele in a dog, with preservation of vision and absence of any significant postoperative complications.