Mechanistic insights into m6A modification of U6 snRNA by human METTL16
Mechanistic insights into m6A modification of U6 snRNA by human METTL16
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DOI：
10.1093/nar/gkaa227
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发表时间：
2020-05-21
影响因子：
14.9
通讯作者：
Tomita, Kozo
中科院分区：
文献类型：
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作者：
Aoyama, Tomohiko;Yamashita, Seisuke;Tomita, Kozo
U6 snRNA的43位（m（6）A43）的N-6-甲基腺苷修饰是由胃L16催化的，并且对于U6 snRNA在pre-mRNA剪接过程中的5 '-剪接位点识别是重要的。人胃L16由N-末端甲基转移酶结构域（MTD）和C-末端脊椎动物保守区（VCR）组成。虽然MTD具有在RNA的不同结构背景下识别特定序列的固有特性，但VCR功能仍未表征。在这里，我们提出了人胃L16 VCR的结构和功能分析。长春新碱增加了胃L16与U6 snRNA的亲和力，并且长春新碱中保守的碱性区域对于胃L16-U6 snRNA的相互作用是重要的。VCR结构与U6 snRNA特异性末端尿苷酰转移酶1（TUT 1）中的C末端RNA结合结构域KA 1拓扑同源。胃L16的N-末端MTD和TUT 1的C-末端KA 1的嵌合体比MTD更有效地甲基化U6 snRNA，表明VCR和KA 1对于U6 snRNA生物合成的功能保守。VCR与U6 snRNA内的内部茎环（ISL）相互作用，这种相互作用将诱导U6 snRNA含A43区域的构象重排，从而修饰RNA结构，使其适合MTD的生产性催化。因此，在胃L16中MTD和VCR协同促进m（6）A43 U6 snRNA修饰。
The N-6-methyladenosine modification at position 43 (m(6)A43) 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 m(6)A43 U6 snRNA modification.