Yin-Yang 1 and Yin-Yang 2 exert opposing effects on the promoter activity of interleukin 4 = Yin-Yang 1 and Yin-Yang 2 exert opposing effects on the promoter activity of interleukin 4

다국어 초록 (Multilingual Abstract)

Interleukin (IL)-4 acts on T cells as a growth And activation factor, and promotes the differentiation of Type 2 T helper cells. In T cells, expression of the gene Encoding IL-4 is regulated by inducible or constitutive factors. Yin-Yang (YY)-1 is one of constitutive transcrip-tion factors binding to the IL-4 promoter. The recently identified YY2 protein is similar to YY1, with both sharing high levels of homology in their zinc finger motifs. How-ever, the role of YY2 in T cells is unclear. YY1 and YY2 were constitutively expressed in EL4 T cells, and their expression was not dependent on stimulation. IL-4 pro-moter (-741/+56 fragment) activity was enhanced by YY1, but inhibited by YY2, The enhanced IL-4 promoter activity by YY1 was reduced by simultaneous expression of YY2. In addition, the DNA binding affinity of YY1 to the IL-4 promoter was adversely affected by YY2. Our results suggest that YY1 and YY2 exert opposing effects on the IL-4 promoter as they compete for the same DNA binding sites.