InterPro domain: IPR042036

Ribosomal RNA processing protein 8 (Rrp8) is a nucleolar Rossman-fold like methyltransferase. In yeast, it is involved in pre-rRNA cleavage at site A2 [ 1 ] and is responsible for a base methylation of the 25S rRNA [ 2 ]. In humans it is also known as nucleomethylin (NML), and it is important for mediating the assembly of the energy-dependent nucleolar silencing complex (eNoSC), which regulates rRNA transcription in response to glucose deprivation [ 3 ]. NML represses rDNA transcription by promoting H3K9 methylation and establishing heterochromatin across the rDNA [ 4 ].

This superfamily represents the N-terminal domain of the ribosomal RNA-processing protein 8 (RRP8).

1. Rrp8p is a yeast nucleolar protein functionally linked to Gar1p and involved in pre-rRNA cleavage at site A2. RNA 6, 826-43
2. Yeast Rrp8p, a novel methyltransferase responsible for m1A 645 base modification of 25S rRNA. Nucleic Acids Res. 41, 1151-63
3. Regulation of SirT1-nucleomethylin binding by rRNA coordinates ribosome biogenesis with nutrient availability. Mol. Cell. Biol. 33, 3835-48
4. Epigenetic control of rDNA loci in response to intracellular energy status. Cell 133, 627-39