Structural highlights
Function
[MET16_HUMAN] RNA N6-methyltransferase that methylates adenosine residues of a subset of RNAs and plays a key role in S-adenosyl-L-methionine homeostasis by regulating expression of MAT2A transcripts (PubMed:28525753). Able to N6-methylate a subset of mRNAs and U6 small nuclear RNAs (U6 snRNAs) (PubMed:28525753). In contrast to the METTL3-METTL14 heterodimer, only able to methylate a limited number of RNAs: requires both a 5'UACAGAGAA-3' nonamer sequence and a specific RNA structure (PubMed:28525753). In presence of S-adenosyl-L-methionine, binds the 3'-UTR region of MAT2A mRNA and specifically N6-methylates the first hairpin of MAT2A mRNA, impairing MAT2A expression (PubMed:28525753). In S-adenosyl-L-methionine-limiting conditions, binds the 3'-UTR region of MAT2A mRNA but stalls due to the lack of a methyl donor, preventing N6-methylation and promoting expression of MAT2A (PubMed:28525753). In addition to mRNAs, also able to mediate N6-methylation of U6 small nuclear RNA (U6 snRNA): specifically N6-methylates adenine in position 43 of U6 snRNAs (PubMed:28525753, PubMed:29051200). Also able to bind various lncRNAs (PubMed:29051200). Specifically binds the 3'-end of the MALAT1 long non-coding RNA (PubMed:27872311).[1] [2] [3]
Publication Abstract from PubMed
The N6-methyladenosine modification at position 43 (m6A43) of U6 snRNA is catalyzed by METTL16, and is important for the 5'-splice site recognition by U6 snRNA during pre-mRNA splicing. Human METTL16 consists of the N-terminal methyltransferase domain (MTD) and the C-terminal vertebrate conserved region (VCR). While the MTD has an intrinsic property to recognize a specific sequence in the distinct structural context of RNA, the VCR functions have remained uncharacterized. Here, we present structural and functional analyses of the human METTL16 VCR. The VCR increases the affinity of METTL16 toward U6 snRNA, and the conserved basic region in VCR is important for the METTL16-U6 snRNA interaction. The VCR structure is topologically homologous to the C-terminal RNA binding domain, KA1, in U6 snRNA-specific terminal uridylyl transferase 1 (TUT1). A chimera of the N-terminal MTD of METTL16 and the C-terminal KA1 of TUT1 methylated U6 snRNA more efficiently than the MTD, indicating the functional conservation of the VCR and KA1 for U6 snRNA biogenesis. The VCR interacts with the internal stem-loop (ISL) within U6 snRNA, and this interaction would induce the conformational rearrangement of the A43-containing region of U6 snRNA, thereby modifying the RNA structure to become suitable for productive catalysis by the MTD. Therefore, the MTD and VCR in METTL16 cooperatively facilitate the m6A43 U6 snRNA modification.
Mechanistic insights into m6A modification of U6 snRNA by human METTL16.,Aoyama T, Yamashita S, Tomita K Nucleic Acids Res. 2020 May 21;48(9):5157-5168. doi: 10.1093/nar/gkaa227. PMID:32266935[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Brown JA, Kinzig CG, DeGregorio SJ, Steitz JA. Methyltransferase-like protein 16 binds the 3'-terminal triple helix of MALAT1 long noncoding RNA. Proc Natl Acad Sci U S A. 2016 Dec 6;113(49):14013-14018. doi:, 10.1073/pnas.1614759113. Epub 2016 Nov 21. PMID:27872311 doi:http://dx.doi.org/10.1073/pnas.1614759113
- ↑ Pendleton KE, Chen B, Liu K, Hunter OV, Xie Y, Tu BP, Conrad NK. The U6 snRNA m(6)A Methyltransferase METTL16 Regulates SAM Synthetase Intron Retention. Cell. 2017 May 18;169(5):824-835.e14. doi: 10.1016/j.cell.2017.05.003. PMID:28525753 doi:http://dx.doi.org/10.1016/j.cell.2017.05.003
- ↑ Warda AS, Kretschmer J, Hackert P, Lenz C, Urlaub H, Hobartner C, Sloan KE, Bohnsack MT. Human METTL16 is a N(6)-methyladenosine (m(6)A) methyltransferase that targets pre-mRNAs and various non-coding RNAs. EMBO Rep. 2017 Nov;18(11):2004-2014. doi: 10.15252/embr.201744940. Epub 2017 Oct , 19. PMID:29051200 doi:http://dx.doi.org/10.15252/embr.201744940
- ↑ Aoyama T, Yamashita S, Tomita K. Mechanistic insights into m6A modification of U6 snRNA by human METTL16. Nucleic Acids Res. 2020 May 21;48(9):5157-5168. doi: 10.1093/nar/gkaa227. PMID:32266935 doi:http://dx.doi.org/10.1093/nar/gkaa227
