Arginine methylation of recombinant murine fibrillarin by protein arginine methyltransferase.

Fibrillarin is a conserved nucleolar SnoRNP with a diverse N-terminal glycine- and arginine-rich (GAR) domain in most eukaryotes. This region in human fibrillarin is known to contain modified dimethylarginines. In this report we demonstrate that recombinant murine fibrillarin is a substrate for protein arginine methyltransferase, including the purified recombinant enzyme (rat PRMT1 and yeast RMT1) and the protein methyltransferases present in lymphoblastoid cell extracts.

Proteomic analysis of stable protein methylation in lymphoblastoid cells.

We investigated the global distribution of methylaccepting proteins in lymphoblastoid cells by two-dimensional (2-D) gel electrophoresis. The 2-D electrophoreograms of normal and hypo-methylation (cells grown with a methyltransferase inhibitor adenosine dialdehyde) protein extracts did not exhibit significant differences. However, in vitro methylation of the hypomethylated extracts in the presence of the methyl-group donor S-adenosyl-[methyl-3H]-methionine revealed close to a hundred signals.