Casey Eye Institute, Department of Ophthalmology, Oregon Health and Sciences University, Portland, Oregon 97239, USA.
J Comp Neurol. 2010 Feb 15;518(4):513-25. doi: 10.1002/cne.22234.
Secretagogin, a recently cloned member of the EF-hand family of calcium binding proteins, was localized in the mouse, rat, and rabbit retina using immunofluorescence immunohistochemistry. Secretagogin is expressed in subpopulations of ON and OFF cone bipolar cells; however, no immunoreactivity was observed in rod bipolar cells in any of these species. Using subtype-specific markers and mice expressing green fluorescent protein (GFP) within specific cell classes, we found that secretagogin is expressed in Types 2, 3, 4, 5, 6 and possibly Type 8 cone bipolar cells in the mouse retina. The expression pattern in the rat retina differs slightly with expression in cone bipolar cell Types 2, 5, 6, 7, and 8. Evaluation of secretagogin in the developing mouse retina revealed expression as early as postnatal day 6, with OFF cone bipolar cells showing secretagogin expression prior to the ON cone bipolar cells. Secretagogin is a useful marker of cone bipolar cells for studying alterations in bipolar cell morphology during development and degeneration. Further work will be necessary to elucidate the functional role of this protein in bipolar cells.
分泌素是 EF 手钙结合蛋白家族的一个新成员，通过免疫荧光组织化学方法对其在小鼠、大鼠和兔子视网膜中的定位进行了研究。分泌素在 ON 和 OFF 锥形双极细胞的亚群中表达；然而，在这些物种的任何一种中，都没有观察到杆状双极细胞的免疫反应性。使用亚型特异性标志物和在特定细胞类群中表达绿色荧光蛋白 (GFP) 的小鼠，我们发现分泌素在小鼠视网膜中的 Type 2、3、4、5、6 型和可能的 Type 8 锥形双极细胞中表达。在大鼠视网膜中的表达模式略有不同，在锥形双极细胞 Type 2、5、6、7 和 8 中表达。对发育中小鼠视网膜中分泌素的评估表明，其表达早在出生后第 6 天就出现了，OFF 锥形双极细胞的表达先于 ON 锥形双极细胞。分泌素是研究双极细胞在发育和变性过程中形态变化的锥形双极细胞的有用标志物。进一步的工作将需要阐明该蛋白在双极细胞中的功能作用。
