Methylation of translation elongation factor 1A by the METTLlO-like Seel methyltransferase facilitates tombusvirus replication in yeast and plants

摘要

Replication of tombusviruses and other plus-strand RNA viruses depends on several host factors that are recruited into viral replicase complexes. Previous studies have shown that eukaryotic translation elongation factor 1A (eEFIA) is one of the resident host proteins in the highly purified tombusvirus replicase complex. In this paper, we show that methylation of eEFIA by the METTLIO-Iike Seelp methyltransferase is required for tombusvirus and unrelated nodavirus RNA replication in yeast model host. Similar to the effect of SEE1 deletion, yeast expressing only a mutant form of eEFIA lacking the 4 known lysines subjected to methylation supported reduced TBSV accumulation. We show that the half-life of several viral replication proteins is decreased in seel A yeast or when a mutated eEFIA was expressed as a sole source for eEFIA. Silencing of the plant ortholog of Seel methyltransferase also decreased tombusvirus RNA accumulation in Nicotiana benthamiana.