Study On Relationship Between CBP And STAT4/STAT6 In Fuction Activity And Explore Their Relationship With Th1/Th2 Cell Disfuction

In tne family of STATs, STAT4 and STAT6 play a very important role in Th1/Th2 cell disfunction. IL-12 induce IFN-γmRNA transcription by activating STAT4, IL-4 induce IL-4R promoter mRNA transcription by activating STAT6. Studys show that many transcription factors can bind with CBP competively, CBP play a very important role in gene transcription process which are induced by STAT4/STAT6.AIM :To investigate the relatinoship between STAT4 and STAT6 in fuction activity.Can CBP sever the competive relationgship of STAT4/STA6.METHOD:The gene encoding IFN-γpromrtor was obtained by PCR and then cloned into the eukaryotic expression vector pCAT3-Enhancer. The gene encoding IL-4 receptor promrtor was obtained by PCR and then cloned into the eukaryotic expression vector pGL3-Control. These constructed plasmid and eukaryotic expression plasmid of CBP were transfected into the human T cell line Jurkat cells. The expression of LUC and CAT were detected by LUC assay and CAT assay after the addition of IL-12 and IL-4.RESULT :The DNA sequencing analysis and restriction enzyme digestion results showded that the recombinant plasmid pCAT3-IFN-γand pGL3-IL-4R were successfully constructed. The result of LUC and CAT detection assay showed that when activited STAT4 were increasing, the expression of LUC was decreased, and when activited STAT6 were increasing, the expression of CAT was decreased.There was no regulation in the decreasing of LUC or CAT when CBP was increasing.CONCLUSION : When activited STAT4 were increasing the activition of STAT6 were decreased, when activited STAT6 were increasing, the activition of STAT4 was decreased. Our results showed that STAT4 and STAT6 are competitor in gene transcription process.CBP can not sever their competive relationship.