Objective    To determine the positions of transcription regulation elements in 5’ flanking region of human Na

+

dependent dicarboxylate transporter 1 (hNaDC1) gene.     Methods    The DNA fragments hNaDC1 A-E（-2 232/+136）of its 5’ flanking were amplified from the genomic DNAs of HK-2 cells by using PCR. The PCR products were directionally subcloned into pGL3-basic vector. The recombined clones were identified by agarose gel electrophoresis after restriction endonuclease digesting and DNA sequencing. The recombined vectors as well as pGL3-basic vector were respectively transfected into HK-2 cells with Lipofectamine 2000. To norma

lize transfection efficiencies

0.4 μg of a Renilla luciferase positive control vector (pRL-CMV plasmid) was used for co-transfection.The interaction between transcription regulation elements and transcription regulation proteins in 5’ flanking region of hNaDC1 gene（-2 232/+136）was measured by analyzing relative light unit (RLU) with the help of Dual Luciferase Report Gene Assay System (DLR).     Results    The RLU was significantly lowered in HK-2 cells transfected with pGl3-basic when compared with the cells harboring pGL3-hNaDC1 A-E (P0.05 or P0.001). Compared with pGL3-hNaDC1 A group

RLU was significantly lowered in pGL3-hNaDC1 D group (P0.01) and pGL3-hNaDC1 E group (P0.05). MatInspector 5.0 system indicated that there were 22 binding sites of 14 trans-acting factors(Sore90) in the regions -1 084/-254 and -12/+136.     Conclusion    Transcription enhancer elements

which have interacted with transcription activation proteins

exist in both region -1 084/-254 and -12/+136. These results may offer an approach for further study on the enhancers of hNaDC1 gene.