Yeast Hsl7 (histone synthetic lethal 7) catalyses the in vitro formation of omega-N(G)-monomethylarginine in calf thymus histone H2A.
The HSL7 (histone synthetic lethal 7) gene in the yeast Saccharomyces cerevisiae encodes a protein with close sequence similarity to the mammalian PRMT5 protein, a member of the class of protein arginine methyltransferases that catalyses the formation of omega-N(G)-monomethylarginine and symmetric omega-N(G),N'(G)-dimethylarginine residues in a number of methyl-accepting species. A full-length HSL7 construct was expressed as a FLAG-tagged protein in Saccharomyces cerevisiae. We found that FLAG-tagged Hsl7 effectively catalyses the transfer of methyl groups from S-adenosyl-[methyl-3H]-L-methionine to calf thymus histone H2A. When the acid-hydrolysed radiolabelled protein products were separated by high-resolution cation-exchange chromatography, we were able to detect one tritiated species that co-migrated with an omega-N(G)-monomethylarginine standard. No radioactivity was observed that co-migrated with either the asymmetric or symmetric dimethylated derivatives. In control experiments, no methylation of histone H2A was found with two mutant constructs of Hsl7. Surprisingly, FLAG-Hsl7 does not appear to effectively catalyse the in vitro methylation of a GST (glutathione S-transferase)-GAR [glycine- and arginine-rich human fibrillarin-(1-148) peptide] fusion protein or bovine brain myelin basic protein, both good methyl-accepting substrates for the human homologue PRMT5. Additionally, FLAG-Hsl7 demonstrates no activity on purified calf thymus histones H1, H2B, H3 or H4. GST-Rmt1, the GST-fusion protein of the major yeast protein arginine methyltransferase, was also found to methylate calf thymus histone H2A. Although we detected Rmt1-dependent arginine methylation in vivo in purified yeast histones H2A, H2B, H3 and H4, we found no evidence for Hsl7-dependent methylation of endogenous yeast histones. The physiological substrates of the Hsl7 enzyme remain to be identified.
Miranda
Tina Branscombe
TB
The Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA (University of California, Los Angeles), Los Angeles, CA 90095-1569, USA.
Sayegh
Joyce
J
Frankel
Adam
A
Katz
Jonathan E
JE
Miranda
Mark
M
Clarke
Steven
S
D000595:Amino Acid Sequence; D000818:Animals; D002384:Catalysis; D002417:Cattle; D015870:Gene Expression; D006657:Histones / Q000302:isolation & purification / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011484:Protein-Arginine N-Methyltransferases; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013379:Substrate Specificity; D013950:Thymus Gland; D019323:omega-N-Methylarginine / Q000096:biosynthesis* / Q000378:metabolism
D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; D019323:omega-N-Methylarginine; D008780:Methyltransferases; C077013:PRMT2 protein, human; D011484:Protein-Arginine N-Methyltransferases; C120666:HSL7 protein, S cerevisiae; D011494:Protein Kinases