Study The Negative Regulation Of TGFβ Signal Pathway By The Interactilon Of GATA2 And Smad4

GATA2 is a member of the zinc finger transcription factor GATA family. It is highly expressed in hematopoietic stem/progenitor cells, and plays a critical role in proliferation , differetiation and the self-renewal of HSCs. TGFβsignal pathway takes part in multiple physiological pathological process including the self- renewal process of HSCs. Smad4 is the common smad protein which is crucial for TGFβsignal pathway. We used large scale Yeast two-hybrid (YTH) which is established by our lab,and on this bias,we indentified the interaction between GATA2 and Smad4 . In the present study, we confirmed the interaction between GATA2 and Smad4 by Co-IP.Luciferase reporter assay proved that GATA2 repressed the transcriptional activity mediated by Smad4,and other R-Smads, and also down- regulate the activity of TGFβ.Using the same method,we prove that PAI-1, the target gene of TGFβsignal pathway, is resulting in the down-regulation by GATA2 .Furthermore,We found that the The transcriptional repression domain of GATA2 is mapped to N terminal and the zinic finger. We indentify that the GATA2 could down regulate the sensitivity of Huh7 cell line under the TGFβ.To further study in ES cells, we constructed the lentiviral vector containing human GATA2 gene and GATA2 lentiviral interfering vector ,and also established an expression system, and then produced the GATA2 lentivrirus and GATA2 RNAi lentivrirus,which are prepared for the further research.All these data suggest that GATA2 interact with Smad4 and negatively regulated TGFβsignal pathway. The negative regulation of GATA2 on TGFβsignal pathway may play a critical role in the self-renewal and differentiation of HSC.