Required for proper assembly of pre-ribosomal particles during the biogenesis of the 60S ribosomal subunit. Specifically methylates the guanosine in position 2922 of the 25S rRNA at the stage of 27S pre-rRNA maturation. Methylates also the uridine in position 2921 in the absence of methylation of this residue guided by snoRNA snR52 at the stage of 35S pre-rRNA maturation. guanosine(2922) in 27S pre-rRNA + S-adenosyl-L-methionine = 2'-O-methylguanosine(2922) in 27S pre-rRNA + H(+) + S-adenosyl-L-homocysteine Component of the nucleolar and nucleoplasmic pre-60S ribosomal particle. Interacts with the snoRNA-associated proteins NOP1 and NOP58. Belongs to the class I-like SAM-binding methyltransferase superfamily. RNA methyltransferase RlmE family. SPB1 subfamily.