Tang Louisa S, Alger Heather M, Lin Feng, Pereira Fred A
Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA.
Gene Expr Patterns. 2005 Jun;5(5):587-92. doi: 10.1016/j.modgep.2005.03.012.
COUP-TFs (chicken ovalbumin upstream promoter-transcription factors) are orphan members of the nuclear receptor superfamily of ligand-activated receptors for which their ligands have not been identified. The two mammalian proteins, COUP-TFI and COUP-TFII, share 80% sequence identity and regulate many aspects of mammalian development and differentiation. In this report, we systemically examined the temporal and spatial expression of COUP-TFI and COUP-TFII transcripts and, for the first time, their protein during development and functional maturation of the cochlea. Both COUP-TFI and COUP-TFII were expressed early in the developing otic vesicle. COUP-TFI expression correlated with the differentiation of hair cells and support cells in the organ of Corti, whereas COUP-TFII expression was down-regulated with differentiation of the organ of Corti. Furthermore, we report for the first time, that the generally nuclear COUP-TFI receptor protein was localized in the cytoplasm of maturing hair cells and pillar cells. Collectively, although COUP-TFI and COUP-TFII are homologues, the expression of each orphan receptor has a restricted and dynamic expression during cochlea development particularly during patterning and differentiation of the cochlear structures.
COUP转录因子（鸡卵清蛋白上游启动子转录因子）是核受体超家族中配体激活受体的孤儿成员，其配体尚未确定。两种哺乳动物蛋白COUP-TFI和COUP-TFII的序列同一性为80%，并调节哺乳动物发育和分化的许多方面。在本报告中，我们系统地研究了COUP-TFI和COUP-TFII转录本以及首次在耳蜗发育和功能成熟过程中的蛋白质的时空表达。COUP-TFI和COUP-TFII在发育中的耳囊中均早期表达。COUP-TFI的表达与柯蒂氏器中毛细胞和支持细胞的分化相关，而COUP-TFII的表达随着柯蒂氏器的分化而下调。此外，我们首次报道，通常位于细胞核中的COUP-TFI受体蛋白定位于成熟毛细胞和柱细胞的细胞质中。总的来说，尽管COUP-TFI和COUP-TFII是同源物，但每个孤儿受体在耳蜗发育过程中，特别是在耳蜗结构的模式形成和分化过程中，具有受限且动态的表达。
