Required for efficient pre-35S rRNA cleavage at site A2. Remains associated to the resulting 27S product. Also involved in telomere length regulation and maintenance. This nucleolar Rossmann-fold like protein is highly conserved in eukaryotes and catalyses the N1-methylation of A645 in helix 25.1 of 25S rRNA. However the methylation function is independent of the A2-cleavage reaction, attesting that Rrp8p has a dual function. The introduction of a methyl group at N1 of adenosine, introduces a positive charge to the nucleoside.