[Effects of transcription factor GATA-2 on transcriptive regulation of iASPP gene].

iASPP can prompt the cell proliferation and inhibit the apoptosis of many cells.There are putative binding sites of transcription factor GATA-2 upstream of iASPP transcription start site.GATA-2 plays an important role in the proliferation and differentiation of hematopoietic stem cells(HSC) and progenitors.This study was aimed to explore the role of GATA-2 protein in iASPP gene transcription.Firstly,the expression of iASPP and GATA-2 protein in some leukemia cell lines was detected by Western blot.Second,The expressive vector of pCMV5-GATA2 and the luciferase reporter vectors containing possible binding sites of GATA-2 were constructed and co-transfected into HEK293 and CV-1 cells.Then the luciferase activity was assayed by luminometer.Also,ChIP assays were performed to further confirm the specific binding of GATA-2 to iASPP promoter.The results showed that GATA-2 was overexpressed in most cell lines with high level of iASPP.GATA-2 exhibited a significant effect on luciferase activity of reporter gene iASPP and in a dose-dependant manner.The relative luciferase activity was up-regulated to about two-fold of the empty vector control when the transfection dose of pCMV5-GATA2 plasmid was increased to 100 ng.While the effect was more significant in CV-1 cells and showed a 6.7-fold increase.The ChIP assay demonstrated the in vivo specific binding of GATA-2 to iASPP.The binding sites of GATA2 were located between nt-361~-334 in upstream of iASPP gene transcription start site.It is concluded that transcription factor GATA-2 can bind with the cis-regulatory region of the iASPP promoter and up-regulate iASPP expression.