DNA substrate recognition and processing by the full-length human UPF1 helicase.
DNA substrate recognition and processing by the full-length human UPF1 helicase.
复制标题
DOI：
10.1093/nar/gkx478
复制
发表时间：
2017-07-07
影响因子：
14.9
通讯作者：
Sanders CM
中科院分区：
文献类型：
--
作者：
Dehghani-Tafti S;Sanders CM
UPF1是一种保守的解旋酶，是无义介导的衰变（NMD）调节细胞质中mRNA稳定性所必需的。人UPF1（hUPF1）也是核DNA复制所必需的。虽然NMD的丧失是可耐受的，但hUPF1的丧失诱导DNA损伤反应和细胞周期停滞。我们分析了核酸（NA）的结合和处理全长hUPF1。hUPF1在体外解旋非B型和B型DNA和RNA底物。与许多参与基因组稳定性的解旋酶不同，没有观察到hUPF1与通过碱基对间氢键稳定的DNA结构的结合。或者，与嘧啶多核苷酸相比，hUPF1以随底物长度增加的表观亲和力结合单链NA（ssNA），并且不优先结合RNA或DNA或嘌呤。然而，数据显示出明显的核碱基偏好，优先结合聚（U）或d（T），而d（A）聚合物以低亲和力结合。尽管数据表明hUPF1必须结合ssNA片段以启动解旋，但它们也提高了hUPF1对具有堆叠碱基的ssNA结构的亲和力显著降低的可能性。总的来说，NA加工活动的hUPF1是一致的，其在mRNA的调节功能，并建议在DNA复制中的作用也可能受到影响的碱基序列。
UPF1 is a conserved helicase required for nonsense-mediated decay (NMD) regulating mRNA stability in the cytoplasm. Human UPF1 (hUPF1) is also needed for nuclear DNA replication. While loss of NMD is tolerated, loss of hUPF1 induces a DNA damage response and cell cycle arrest. We have analysed nucleic acid (NA) binding and processing by full-length hUPF1. hUPF1 unwinds non-B and B-form DNA and RNA substrates in vitro. Unlike many helicases involved in genome stability no hUPF1 binding to DNA structures stabilized by inter-base-pair hydrogen bonding was observed. Alternatively, hUPF1 binds to single-stranded NAs (ssNA) with apparent affinity increasing with substrate length and with no preference for binding RNA or DNA or purine compared to pyrimidine polynucleotides. However, the data show a pronounced nucleobase bias with a preference for binding poly (U) or d(T) while d(A) polymers bind with low affinity. Although the data indicate that hUPF1 must bind a ssNA segments to initiate unwinding they also raise the possibility that hUPF1 has significantly reduced affinity for ssNA structures with stacked bases. Overall, the NA processing activities of hUPF1 are consistent with its function in mRNA regulation and suggest that roles in DNA replication could also be influenced by base sequence.