Leucci Eleonora, De Falco Giulia, Onnis Anna, Cerino Giovanna, Cocco Mario, Luzzi Anna, Crupi Domenica, Tigli Chiara, Bellan Cristiana, Tosi Piero, Leoncini Lorenzo, Giordano Antonio
Department of Human Pathology and Oncology, University of Siena, Siena, Italy.
J Cell Physiol. 2007 Aug;212(2):411-5. doi: 10.1002/jcp.21032.
The Cdk9/Cyclin T1 complex is very important in controlling specific differentiative pathways of several cell types, including muscle cells and neurons. We recently demonstrated the involvement of this complex in B cell activation/differentiation. To check whether the Cdk9/Cyclin T1 complex is also involved in the T cell activation/differentiation process, we isolated different T cell populations by magnetic separation, based on their surface antigens. We observed that the expression level of Cdk9/Cyclin T1 increases in effector T cells (CD27(+)), as well as in activated T cells (CD25(+)) and memory T cells (CD45RA(-)), thus suggesting a specific upregulation of the Cdk9/Cyclin T1 complex following antigen encounter. We have previously demonstrated that in B cells, Cdk9 interacts in vivo with the E2A gene products E12/E47 (members of the basic helix-loop-helix family) which are involved in differentiation. In this article, we show that this interaction also occurs in T cells. This suggests an active role for the Cdk9/Cyclin T1 complex during lymphoid differentiation, through physical binding with E12 and E47. These preliminary results suggest that the Cdk9/Cyclin T1 complex may be important in the activation and differentiation program of lymphoid cells and that its upregulation, which is due to still unknown mechanisms, may contribute to malignant transformation.
细胞周期蛋白依赖性激酶9（Cdk9）/细胞周期蛋白T1（Cyclin T1）复合物在控制包括肌肉细胞和神经元在内的多种细胞类型的特定分化途径中非常重要。我们最近证明了该复合物参与B细胞的激活/分化过程。为了检查Cdk9/Cyclin T1复合物是否也参与T细胞的激活/分化过程，我们基于表面抗原通过磁性分离分离出不同的T细胞群体。我们观察到，效应T细胞（CD27(+)）、活化T细胞（CD25(+)）和记忆T细胞（CD45RA( -)）中Cdk9/Cyclin T1的表达水平均升高，这表明抗原接触后Cdk9/Cyclin T1复合物出现特异性上调。我们之前已经证明，在B细胞中，Cdk9在体内与参与分化的E2A基因产物E12/E47（碱性螺旋-环-螺旋家族成员）相互作用。在本文中，我们表明这种相互作用在T细胞中也会发生。这表明Cdk9/Cyclin T1复合物通过与E12和E47的物理结合在淋巴细胞分化过程中发挥积极作用。这些初步结果表明，Cdk9/Cyclin T1复合物可能在淋巴细胞的激活和分化程序中很重要，并且其上调（原因尚不清楚）可能导致恶性转化。
