Identification and characterization of two closely related histone H4 arginine 3 methyltransferases in Arabidopsis thaliana.
Arginine methylation of histone H3 and H4 plays important roles in transcriptional regulation in eukaryotes such as yeasts, fruitflies, nematode worms, fish and mammals; however, less is known in plants. In the present paper, we report the identification and characterization of two Arabidopsis thaliana protein arginine N-methyltransferases, AtPRMT1a and AtPRMT1b, which exhibit high homology with human PRMT1. Both AtPRMT1a and AtPRMT1b methylated histone H4, H2A, and myelin basic protein in vitro. Site-directed mutagenesis of the third arginine (R3) on the N-terminus of histone H4 to lysine (H4R3N) completely abolished the methylation of histone H4. When fused to GFP (green fluorescent protein), both methyltransferases localized to the cytoplasm as well as to the nucleus. Consistent with their subcellular distribution, GST (glutathione transferase) pull-down assays revealed an interaction between the two methyltransferases, suggesting that both proteins may act together in a functional unit. In addition, we demonstrated that AtFib2 (Arabidopsis thaliana fibrillarin 2), an RNA methyltransferase, is a potential substrate for AtPRMT1a and AtPRMT1b, and, furthermore, uncovered a direct interaction between the protein methyltransferase and the RNA methyltransferase. Taken together, our findings implicate AtPRMT1a and AtPRMT1b as H4-R3 protein arginine N-methyltransferases in Arabidopsis and may be involved in diverse biological processes inside and outside the nucleus.
National Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Dongsheng
D
Yan
Yong
Y
Zhang
Lifang
L
Niu
Yi
Y
Yuan
Xiaofeng
X
Cao
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D017124:Conserved Sequence; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008745:Methylation; D008780:Methyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011484:Protein-Arginine N-Methyltransferases; D012680:Sensitivity and Specificity; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D047908:Intracellular Signaling Peptides and Proteins; D008780:Methyltransferases; C077013:PRMT2 protein, human; D011484:Protein-Arginine N-Methyltransferases