This family includes ribosomal RNA large subunit methyltransferase F, and related proteins, including methyltransferase-like protein 16 (METTL16). METTL16 is a conserved RNA methyltransferase which interacts specifically with the MALAT1 triple helix. METTL16 shows nuclear localisation [1]. Another functional study indicates that METTL16 regulates expression of human MAT2A, which encodes the SAM synthetase expressed in most cells. Furthermore, results indicate that METTL16 is the long-unknown methyltransferase for the U6 spliceosomal small nuclear RNA (snRNA) and it has evolved an additional function in vertebrates to control SAM homeostasis by post-transcriptionally regulating SAM synthetase gene expression [2].

1: Methyltransferase-like protein 16 binds the 3'-terminal triple helix of MALAT1 long noncoding RNA. Brown JA, Kinzig CG, DeGregorio SJ, Steitz JA; Proc Natl Acad Sci U S A. 2016;113:14013-14018. PMID:27872311

2: The U6 snRNA m6A Methyltransferase METTL16 Regulates SAM Synthetase Intron Retention. Pendleton KE, Chen B, Liu K, Hunter OV, Xie Y, Tu BP, Conrad NK; Cell. 2017;169:824-835. PMID:28525753