The transcription factor of cyclin-dependent kinase 2 (cdk2) gene.

CDK2是一种蛋白激酶，其活性在细胞周期中发生变化。推测这种活性的变化伴随着基因转录速率和翻译后修饰的变化。我们发现CDK2mRNA在G1/S期开始增加，在S期达到最大水平，之后下降。我们发现CDK2的转录数量在细胞周期中发生了变化。为了确定该基因参与细胞周期依赖性调控的DNA区域，克隆了小鼠CDK2基因。并亚克隆了+68bp至5‘上游各位点的片段，制备了荧光素酶报告基因。将这些报告基因导入CHO细胞，获得了稳定的转化子。在这些稳定转化子的细胞周期同步化后，检测荧光素酶的活性。我们的研究表明，荧光素酶的表达需要+68bp到-419bp的区域。我们还研究了CDK2的翻译后修饰。提示CDK家族蛋白的活性随着蛋白的磷酸化和去磷酸化而改变，而对激酶(S)和磷酸酶(S)的了解还不是很清楚。Wee1被认为是其中的一种，我们克隆了小鼠Wee1的cDNA。该克隆全长2258个核苷酸，开放阅读框对应646个氨基酸残基。将此小鼠Wee1克隆插入到空泡病毒转移载体中，并对其进行了磷酸化研究。得到的结果是：1)小鼠Wee1蛋白N-末端的氨基酸残基被磷酸化；2)小鼠Wee1使cdc2激酶磷酸化。我们也研究了小鼠Wee1是否也使CDK2磷酸化。

cdk2 is a protein kinase and its activity changes during the cell cycle. It is postulated that this change of activity follows the change of transcription rate of the gene and post-translational modification. We found the mRNA of cdk2 begun to increase at G1/S and reached to the largest level at S-phase then declined thereafter. We showed that the transcription amount of cdk2 changed during the cell cycle. To determine the DNA region which involved in the cell-cycle dependent regulation of the gene, mouse cdk2 gene was cloned. And fragments from+68bp to various sites of 5'upstream region were subcloned, and luciferase reporters were prepared. These reporters were transfected into CHO cells, and stable transformants were obtained. After synchronization of the cell cycle of these stable transformants, the activities of luciferase were assayd. We showed that the region from +68bp to- 419bp was required for cell-cycle dependent expression of luciferase. We also studied the post-translational modification of cdk2. It is suggested that the activity of cdk family proteins changes with their phospyorylation and dephosphorylation, however, the kinase (s) and phosphatase (s) are not well understood. wee1 is postulated as the one of such kinases, and we cloned cDNA of mouse wee1. This clone consisted with 2258bp and its open reading frame corresponds to a 646 amino acid residues. This mouse wee1 clone was inserted into vaculovirus transfer vector, and studied on phosphorylation. The results obtained were 1) mouse wee1 was inactivated by a phosphorylation of an amino acid residue of N-terminal region of the protein, 2) mouse wee1 phosphorylated the cdc2 kinase. We study if mouse wee1 phosphorylates cdk2, as well.