<p>This protein family was first proposed to be RNA methyltransferases by homology to the TrmA family. The member from <taxon tax_id="562">Escherichia coli</taxon> has now been shown to act as the 23S RNA methyltransferase for the conserved U1939. The gene is now designated rumA and was previously designated ygcA [<cite idref="PUB00015406"/>].</p>