This domain is functionally uncharacterised and it is found in the central region of fungal SPB1 and mammalian homologue FTSJ3. This domain is found associated with Pfam:PF07780, Pfam:PF01728. SPB1 is an adoMet-dependent rRNA methyltransferase required for proper assembly of pre-ribosomal particles during the biogenesis of the 60S ribosomal subunit [1]. FTSJ3, SPB1 homologue in humans, is associated with NIP7 (involved in the biogenesis of 40S subunit) and functions in pre-rRNA processing [2].

1: Spb1p is a putative methyltransferase required for 60S ribosomal subunit biogenesis in Saccharomyces cerevisiae. Kressler D, Rojo M, Linder P, Cruz J; Nucleic Acids Res 1999;27:4598-4608. PMID:10556316

2: The human nucleolar protein FTSJ3 associates with NIP7 and functions in pre-rRNA processing. Morello LG, Coltri PP, Quaresma AJ, Simabuco FM, Silva TC, Singh G, Nickerson JA, Oliveira CC, Moore MJ, Zanchin NI; PLoS One. 2011;6:e29174. PMID:22195017