ジャーナル: Nucleic Acids Res / 年: 2025 タイトル: Cryo-EM structure of human TUT1:U6 snRNA complex. 著者: Seisuke Yamashita / Kozo Tomita / 要旨: U6 snRNA (small nuclear ribonucleic acid) is a ribozyme that catalyzes pre-messenger RNA (pre-mRNA) splicing and undergoes epitranscriptomic modifications. After transcription, the 3'-end of U6 snRNA ...U6 snRNA (small nuclear ribonucleic acid) is a ribozyme that catalyzes pre-messenger RNA (pre-mRNA) splicing and undergoes epitranscriptomic modifications. After transcription, the 3'-end of U6 snRNA is oligo-uridylylated by the multi-domain terminal uridylyltransferase (TUTase), TUT1. The 3'- oligo-uridylylated tail of U6 snRNA is crucial for U4/U6 di-snRNP (small nuclear ribonucleoprotein) formation and pre-mRNA splicing. Here, we present the cryo-electron microscopy structure of the human TUT1:U6 snRNA complex. The AUA-rich motif between the 5'-short stem-loop and the telestem of U6 snRNA is clamped by the N-terminal zinc finger (ZF)-RNA recognition motif and the catalytic Palm of TUT1, and the telestem is gripped by the N-terminal ZF and the Fingers, positioning the 3'-end of the telestem in the catalytic pocket. The internal stem-loop in the 3'-stem-loop of U6 snRNA is anchored by the C-terminal kinase-associated 1 domain, preventing U6 snRNA from dislodging on the TUT1 surface during oligo-uridylylation. TUT1 recognizes the sequence and structural features of U6 snRNA, and holds the entire U6 snRNA body using multiple domains to ensure oligo-uridylylation. This highlights the specificity of TUT1 as a U6 snRNA-targeting TUTase.
解像度: 3.21 Å / 解像度の算出法: FSC 0.143 CUT-OFF / 粒子像の数: 263158 詳細: This map (1300050518) is a composite map prepared with 1300050515, 1300050516, and 1300050517. 対称性のタイプ: POINT