Symmetric Di-Methyl Histone H3 (Arg8) (E1W5H) Rabbit mAb #13939

The nucleosome is the primary chromatin building block and consists of DNA wrapped around an octamer made of paired histone proteins H2A, H2B, H3, and H4. Chromatin remodeling plays a critical role in the regulation of various nuclear activities, including transcription. Histone proteins are targets of post-translational modification, including acetylation, phosphorylation, ubiquitination, and methylation. Modified histone residues are recognized and bound by chromatin modifiers and the transcription machinery to regulate gene expression (1-4). Protein arginine methyltransferases (PRMTs) methylate histone proteins at arginine residues to generate mono-methylated, symmetrically di-methylated, or asymmetrically di-methylated proteins. Asymmetrically di-methylated arginine residues are found on histone H3 (Arg2, 8, 17, 26, and 42), histone H4 (Arg3), and histone H2A (Arg3) proteins. Asymmetric methylation is carried out by type 1 PRMTs, which include PRMT1, PRMT2, PRMT4/CARM1, and PRMT6. These modifications are often associated with actively transcribed genes. Symmetric di-methylation of arginine residues are found on histone H3 (Arg2 and 8), histones H4 (Arg3), and H2A (Arg3). Symmetrically di-methylated histone arginine residues are generated by type II transferases PRMT5 and PRMT7, and are often associated with transcription repression (5-9). Arginine residues can also be deiminated by a peptidyl arginine deiminase (PADI) to form the non-coded amino acid citrulline. Conversion of arginine to citrulline prevents methylation of this residue and is thought to regulate histone arginine methylation levels (10-13).