Jaumot M, Graña X, Giordano A, Reddy P V, Agell N, Bachs O
Department of Cell Biology, Faculty of Medicine, University of Barcelona, Spain.
Biochem Biophys Res Commun. 1994 Sep 30;203(3):1527-34. doi: 10.1006/bbrc.1994.2359.
Two different fractions of cdk2 and cdc2 have been found in the nucleus of HeLa cells. One, which can be extracted by nuclease treatment, possibly associated with DNA- or RNA-containing structures and another one, which is bound to the nuclear matrix. Nuclear cdk2 forms high molecular weight complexes which migrate at the same position as DNA polymerase alpha and proliferating cell nuclear antigen in sucrose gradient centrifugation experiments. These results suggest that nuclear cdk2 complexes could be associated with the replication factories. Immunoprecipitation experiments reveal that nuclear cdk2 complexes display histone H1-kinase activity and phosphorylate a protein of 18 kDa which is present in these complexes.
在HeLa细胞核中发现了cdk2和cdc2的两种不同组分。一种可通过核酸酶处理提取，可能与含DNA或RNA的结构相关；另一种则与核基质结合。核cdk2形成高分子量复合物，在蔗糖梯度离心实验中，其迁移位置与DNA聚合酶α和增殖细胞核抗原相同。这些结果表明，核cdk2复合物可能与复制工厂相关。免疫沉淀实验显示，核cdk2复合物具有组蛋白H1激酶活性，并使这些复合物中存在的一种18 kDa蛋白磷酸化。
