维甲酸X受体(retinoid X receptor,RXR)作为配体依赖的转录因子,是核受体超家族重要的一员。脊椎动物RXR与配体及其辅调节因子相互作用,调控基因的协调表达,在胚胎发育、细胞分化、新陈代谢等许多生理过程中起着重要作用。软体动物RXR的研究因其与腹足类性畸变的关系越来越受到关注。本文综述了目前获得的软体动物RXR基因的结构,比较了软体动物RXR基因各功能结构域与人类和其他动物RXR的相似性。以RXR编码区的氨基酸序列为基础,构建了系统进化树,发现软体动物RXR与脊索动物而不是其他无脊椎动物的RXR聚成一支。软体动物和甲壳动物不同RXR亚型的氨基酸序列比较发现,两类动物可能存在不同的剪切酶或剪切位点。此外论文还针对软体动物RXR的配体、二聚体伙伴以及生理功能等方面的研究进行了综述。
Abstract:
Retinoid X receptor (RXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors that have been characterized in a wide variety of species. In vertebrates, RXR functions as either homo-or hetero-dimers to regulate expression of target genes. RXR is important in a variety of physiological events including embryo development, cell-proliferation, metabolism and regeneration. The investigation of molluscan RXR is of particular interest due to its involvement in neogastropods imposex. In this review, we compared the amino acid sequence of molluscan RXRs with human RXRα and other vertebrate RXRs and performed phylogenetic analyses. Parsimony analyses of 22 invertebrate and vertebrate RXRs indicated that the molluscan RXRs were analogous to chordate RXRs. The alignment of amino acid of different isoforms of molluscs and crustaceans indicated that different cutting enzymes or splice sites should exist in T-box. In addition, we discussed the ligand, dimer partner, and physiological function of molluscan RXRs.
