Anti-Histone H3 (asymmetric di methyl R17) antibody,Abcam,AB8284

The nuclear hormone receptor co-activator CARM1 has the potential to methylate histone H3 at arginine residues in vitro. The methyltransferase activity of CARM1 is necessary for its co-activator functions in transient transfection assays. However, the role of this methyltransferase in vivo is unclear, given that methylation of arginines is not easily detectable on purified histones. This antibody recognizes methylated arginine 17 (R17) of histone H3, the major site of methylation by CARM1. Bauer et al (2001) have shown by using this antibody that methylated R17 exists in vivo. Chromatin immunoprecipitation analysis shows that R17 methylation on histone H3 is dramatically upregulated when the estrogen receptor-regulated pS2 gene is stimulated by estradiol and TPA. Coincident with the appearance of methylated R17, the CARM1 methyltransferase is found associated with the histones on the pS2 gene. Together these results demonstrate that the CARM1 methyltransferase is recruited to an active promoter and that CARM1-mediated methylation of histone H3 at R17 takes place in vivo during this active state.