Specificity of a nucleolar 2'-O-methyltransferase for RNA substrates

In this study we examined the specificity of a nucleolar 2'-O-methyltransferase isolated from nucleoli of Ehrlich ascites tumor cells. The nucleolar methyltransferase was capable of methylating each of the four nucleosides of RNA, however, the level of methylation at a particular nucleoside varied with the type of RNA. Both kinetic analysis and the stimulation of methylation by polyamines suggested that the structure of RNA was critical in influencing the discrimination and apparent specificity of nucleolar 2'-O-methyltransferase.