DeLoia J A, Burlingame J M, Krasnow J S
Magee-Womens Research Institute, University of Pittsburgh, PA 15213, USA.
Placenta. 1997 Jan;18(1):9-16. doi: 10.1016/s0143-4004(97)90066-7.
Cyclins are proteins that support the progression of cell-cycle stages in proliferating cells. The purpose of this study was to determine which of the cyclin genes is involved in the regulation of normal human trophoblast proliferation. The presence and cellular localization of four G1 cyclins D1, D2, D3 and E, were determined by immunohistochemistry. This analysis indicated that cyclins E and D3 are the predominant cyclins in villous trophoblast. D2 was present only within the villous core, in fetal macrophages. Positive immunoreactivity for cyclin D1 was strongest in second and third trimester placentae, in the cells lining the intravillous vessels with additional reactivity in extravillous cytotrophoblasts. Because cyclin E protein was present in a greater percentage of cells than those that are dividing, Western blot analysis was performed to validate the fidelity of the immunohistochemistry data. The results of the Western analysis revealed that two forms of cyclin E protein of the appropriate size were present. Data collected from this study suggest that within the trophoblast lineage, cyclins D3 and E are important cell cycle regulatory proteins, and further, that cyclin E may function in trophoblast terminal differentiation as well.
细胞周期蛋白是一类支持增殖细胞中细胞周期各阶段进程的蛋白质。本研究的目的是确定哪些细胞周期蛋白基因参与正常人滋养层细胞增殖的调控。通过免疫组织化学方法确定了四种G1期细胞周期蛋白D1、D2、D3和E的存在及细胞定位。该分析表明，细胞周期蛋白E和D3是绒毛滋养层细胞中的主要细胞周期蛋白。D2仅存在于绒毛核心的胎儿巨噬细胞中。细胞周期蛋白D1的阳性免疫反应性在妊娠中期和晚期胎盘的绒毛内血管内衬细胞中最强，在绒毛外细胞滋养层细胞中也有额外的反应性。由于细胞周期蛋白E蛋白存在于比正在分裂的细胞更大比例的细胞中，因此进行了蛋白质印迹分析以验证免疫组织化学数据的准确性。蛋白质印迹分析结果显示存在两种大小合适的细胞周期蛋白E蛋白形式。本研究收集的数据表明，在滋养层细胞谱系中，细胞周期蛋白D3和E是重要的细胞周期调节蛋白，此外，细胞周期蛋白E可能也在滋养层细胞终末分化中发挥作用。
