RESUMO
BACKGROUND: Appropriate transcriptional regulation is required for cone photoreceptor development and integrity. To date, only a few cis-regulatory elements that control cone photoreceptor-specific expression have been characterised. The alpha-subunit of cone transducin (TαC) is specifically expressed in cone photoreceptors and is required for colour vision. In order to better understand the molecular genetics controlling the initiation of cone photoreceptor-specific expression in vivo, we have utilised zebrafish to identify cis-regulatory elements in the upstream promoter region of the TαC gene. RESULTS: A 0.5 kb TαC promoter fragment is sufficient to direct cone-specific expression in transgenic larvae. Within this minimal promoter, we identify photoreceptor regulatory element-1 (PRE-1), a unique 41 bp sequence. PRE-1 specifically binds nuclear factors expressed in ocular tissue. PRE-1 is not required for cone-specific expression directed from a 2.5 kb TαC promoter. However, PRE-1-like sequences, with potential functional redundancy, are located in this 2.5 kb promoter. PRE-1-rho which has the highest sequence and structural homology to PRE-1 is located in the rhodopsin promoter. Surprisingly, PRE-1 and PRE-1-rho are functionally distinct. We demonstrate that PRE-1, but not PRE-1-rho, is sufficient to enhance expression from a heterologous UV cone promoter. PRE-1 is also sufficient to enhance expression from a heterologous rhodopsin promoter without altering its rod photoreceptor specificity. Finally, mutations in consensus E-box and Otx sites prevent PRE-1 from forming complexes with eye nuclear protein and enhancing photoreceptor expression. CONCLUSIONS: PRE-1 is a novel cis-regulatory module that is sufficient to enhance the initiation of photoreceptor-specific gene expression in differentiating rod and cone photoreceptors.
Assuntos
Regiões Promotoras Genéticas , Elementos Reguladores de Transcrição/genética , Células Fotorreceptoras Retinianas Cones/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Transducina/genética , Peixe-Zebra/genética , Animais , Animais Geneticamente Modificados , Sequência de Bases , Elementos E-Box/genética , Regulação da Expressão Gênica no Desenvolvimento , Imuno-Histoquímica , Larva/genética , Fatores de Transcrição Otx/genética , Sequências Reguladoras de Ácido Nucleico , Rodopsina/genética , Proteínas de Peixe-Zebra/genéticaRESUMO
OBJECTIVE: This research evaluates effects of vestibular stimulation by Comprehensive Motion Apparatus (CMA) in ADHD. METHOD: Children ages 6 to 12 (48 boys, 5 girls) with ADHD were randomized to thrice-weekly 30-min treatments for 12 weeks with CMA, stimulating otoliths and semicircular canals, or a single-blind control of equal duration and intensity, each treatment followed by a 20-min typing tutorial. RESULTS: In intent-to-treat analysis (n = 50), primary outcome improved significantly in both groups (p = .0001, d = 1.09 to 1.30), but treatment difference not significant (p = .7). Control children regressed by follow-up (difference p = .034, d = 0.65), but overall difference was not significant (p = .13, d = .47). No measure showed significant treatment differences at treatment end, but one did at follow-up. Children with IQ-achievement discrepancy > or = 1 SD showed significantly more CMA advantage on three measures. CONCLUSION: This study illustrates the importance of a credible control condition of equal duration and intensity in trials of novel treatments. CMA treatment cannot be recommended for combined-type ADHD without learning disorder.