Arginine methylation of human adenovirus type 5 L4 100-kilodalton protein is required for efficient virus production.
The adenovirus type 5 (Ad5) late region 4 (L4) 100-kDa nonstructural protein (L4-100K) mediates inhibition of cellular protein synthesis and selective translation of tripartite leader (TL)-containing viral late mRNAs via ribosome shunting. In addition, L4-100K has been implicated in the trimerization and nuclear localization of hexon protein. We previously proved that L4-100K is a substrate of the protein arginine methylation machinery, an emergent posttranslational modification system involved in a growing list of cellular processes, including transcriptional regulation, cell signaling, RNA processing, and DNA repair. As understood at present, L4-100K arginine methylation involves protein arginine methyltransferase 1 (PRMT1), which asymmetrically dimethylates arginines embedded in arginine-glycine-glycine (RGG) or glycine-arginine-rich (GAR) domains. To identify the methylated arginine residues and assess the role of L4-100K arginine methylation, we generated amino acid substitution mutations in the RGG and GAR motifs to examine their effects in Ad-infected and plasmid-transfected cells. Arginine-to-glycine exchanges in the RGG boxes significantly diminished L4-100K methylation in the course of an infection and substantially reduced virus growth, demonstrating that L4-100K methylation in RGG motifs is an important host cell function required for efficient Ad replication. Our data further indicate that PRMT1-catalyzed arginine methylation in the RGG boxes regulates the binding of L4-100K to hexon and promotes the capsid assembly of the structural protein as well as modulating TL-mRNA interaction. Furthermore, substitutions in GAR, but not RGG, regions affected L4-100K nuclear import, implying that the nuclear localization signal of L4-100K is located within the GAR sequence.
Koyuncu
Orkide O
OO
Heinrich-Pette-Institute for Experimental Virology and Immunology, Martinistr. 52, 20251 Hamburg, Germany.
Dobner
Thomas
T
D000258:Adenovirus Infections, Human / Q000821:virology; D000260:Adenoviruses, Human / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D019943:Amino Acid Substitution; D001120:Arginine / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D008745:Methylation; D017354:Point Mutation; D012333:RNA, Messenger / Q000378:metabolism; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
C477284:L4-100K protein, adenovirus type 5; D012333:RNA, Messenger; D017361:Viral Nonstructural Proteins; D001120:Arginine