Dou Q P, Molnar G, Pardee A B
Department of Pharmacology, University of Pittsburgh School of Medicine, PA.
Biochem Biophys Res Commun. 1994 Dec 30;205(3):1859-68. doi: 10.1006/bbrc.1994.2887.
Our studies provide evidence for the presence of cyclin D1 in an early G1 cycle-specific DNA binding complex Yi1. Previously we identified several complexes including Yi and E2F that at different times during G0 to S transition bind to three distinct DNA sequences (MT1, MT2, MT3) located in the mouse thymidine kinase upstream promoter. These various complexes contain DNA binding proteins (Sp1, E2F, p110, p60), cyclins A and E, cyclin-dependent kinase 2 (cdk2), and retinoblastoma-related proteins (pRB, p107). Here we report that Yi1 is different from the E2F complexes. Yi1 contains cyclin D1/cdk2 kinase as shown by using specific antibodies to cyclins, cdks and the Yi1 DNA-binding protein in gel retardation, western blotting, and immunoprecipitation assays. Yi1 binding is specific to a consensus sequence different from that of E2F.
我们的研究为细胞周期蛋白D1存在于早期G1期特异性DNA结合复合物Yi1中提供了证据。此前我们鉴定了几种复合物，包括Yi和E2F，它们在从G0期到S期过渡的不同时间与位于小鼠胸苷激酶上游启动子的三个不同DNA序列（MT1、MT2、MT3）结合。这些不同的复合物包含DNA结合蛋白（Sp1、E2F、p110、p60）、细胞周期蛋白A和E、细胞周期蛋白依赖性激酶2（cdk2）以及视网膜母细胞瘤相关蛋白（pRB、p107）。在此我们报告，Yi1与E2F复合物不同。如在凝胶阻滞、蛋白质印迹和免疫沉淀分析中使用针对细胞周期蛋白、细胞周期蛋白依赖性激酶和Yi1 DNA结合蛋白的特异性抗体所示，Yi1包含细胞周期蛋白D1/cdk2激酶。Yi1的结合对与E2F不同的共有序列具有特异性。
