RESUMO
Sox3/SOX3 gene is considered to be one of the earliest neural markers in vertebrates. Despite the mounting evidence that Sox3/SOX3 is one of the key players in the development of the nervous system, limited data are available regarding the transcriptional regulation of its expression. This review is focused on the retinoic acid induced regulation of SOX3 gene expression, with particular emphasis on the involvement of retinoid receptors. Experiments with human embryonal carcinoma cells identified two response elements involved in retinoic acid/retinoid X receptor-dependent activation of the SOX3 gene expression: distal atypical retinoic acid-response element, consisting of two unique G-rich boxes separated by 49 bp, and proximal element comprising DR-3-like motif, composed of two imperfect hexameric half-sites. Importantly, the retinoic acid-induced SOX3 gene expression could be significantly down-regulated by a synthetic antagonist of retinoid receptors. This cell model provides a solid base for further studies on mechanism(s) underlying regulation of expression of SOX3 gene, which could improve the understanding of molecular signals that induce neurogenesis in the stem/progenitor cells both during development and in adulthood.
Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco Neurais/metabolismo , Receptores do Ácido Retinoico/metabolismo , Fatores de Transcrição SOXB1/metabolismo , Animais , Sítios de Ligação , Linhagem Celular Tumoral , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Humanos , Células-Tronco Neurais/efeitos dos fármacos , Neurogênese , Receptores do Ácido Retinoico/efeitos dos fármacos , Elementos de Resposta , Retinoides/farmacologia , Fatores de Transcrição SOXB1/genética , Transdução de SinaisRESUMO
The Amy-locus polymorphism of Drosophila subobscura is used as a model-system for an experimental population genetic study of adaptive significance of alpha-amylase activity on substrates of different carbohydrate compositions. So far, fitness components have not commonly been included in ecological-genetic studies of alpha-amylase polymorphism in this species. In the present paper fitness components are analyzed in relation to different amylase activities in D. subobscura individuals homozygous for "slow" and "fast" Amy allele, associated with substrates of different carbohydrate compositions. The results indicate a significant effect of substrate carbohydrate composition on fitness components of the genotypes homozygous for S or F Amy allele in D. subobscura through their enzyme activity.
Assuntos
Amilases/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/enzimologia , Evolução Molecular , Polimorfismo Genético , Adaptação Fisiológica/genética , Amilases/genética , Animais , Drosophila/genética , Proteínas de Drosophila/genética , Maltose/metabolismo , Amido/metabolismo , Especificidade por SubstratoRESUMO
Biochemical properties of enzyme alpha-amylase were surveyed in Drosophila obscura Old world group of species (D. subobscura, D. ambigua, D. obscura and D. tristis) sampled in the same habitat, with the aim to reveal some ecological and evolutionary aspects of amylase polymorphism, which has been studied extensively in D. subobscura, but not compared with other species in the group. The data obtained show that D. subobscura is distinct from the other three species regarding all biochemical amylase properties. Such a divergence also correlates with the niche breadth and relative abundance of these species in the same habitat.
