Objective   To construct recombinant reporter plasmids containing different Alpha gene segments and Alpha1-TFEB fusion gene and to evaluate the promoter activity of the Alpha gene.

  Methods   Promoter regions of the Alpha gene were predicted using a software Primer 0.5. Five Alpha gene segments with different lengths and a normal TFEB gene promoter (pTFEB) were amplified via polymerase chain reaction, and recombinant reporter plasmids containing different Alpha gene segments and a normal TFEB gene promoter were constructed. Liposome transfection was used to transfect these vectors into the human embryo kidney 293T cells. The promoter activity of the Alpha gene was evaluated via luciferase assay. Meanwhile, the recombinant Alpha1-TFEB plasmid was constructed and transfected into the 293T cells. The TFEB expression of the recombinant Alpha1-TFEB plasmid was then detected via Western blot.

  Results   Recombinant reporter plasmids containing different Alpha gene segments and pTFEB were constructed successfully. Compared with the luciferase activity of pGL3-Basic, that of the groups with Alpha1, Alpha2, Alpha3, Alpha4 and Alpha5 significantly increased (P < 0.01). The luciferase activity also increased significantly in the groups with Alpha1, Alpha2 and Alpha5 compared with that of the pTFEB group (P < 0.01). The TFEB expression of the pGL3-Enhancer-Alpha1-TFEB was significantly higher compared with that of the pGL3-Enhancer group.

  Conclusion   In t(6;11) translocation RCC, the Alpha gene has a strong promoter activity and it enhances TFEB expression. The strongest promoter activity region is in Alpha5 with a sequence from 643 bp to 693 bp.