Human BCDIN3D monomethylates cytoplasmic histidine transfer RNA.
Human BCDIN3D monomethylates cytoplasmic histidine transfer RNA.
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DOI：
10.1093/nar/gkx051
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发表时间：
2017-05-19
影响因子：
14.9
通讯作者：
Tomita K
中科院分区：
文献类型：
--
作者：
Martinez A;Yamashita S;Nagaike T;Sakaguchi Y;Suzuki T;Tomita K
人RNA甲基转移酶BCDIN3D在乳腺癌细胞中过度表达，与乳腺癌的致瘤表型和不良预后相关。在这里，我们证明细胞质 tRNAHis 是人类细胞中 BCDIN3D 的主要靶标。在大肠杆菌中表达的重组人 BCDIN3D 在体外有效地单甲基化细胞质 tRNAHis 的 5΄-单磷酸。在通过CRISPR/Cas9编辑建立的BCDN3D敲除细胞中，细胞质tRNAHis的5΄-单磷酸处的甲基部分丢失，并且敲除细胞中BCDIN3D的外源表达恢复了细胞质tRNAHis的修饰。 BCIDN3D 可识别 -1 位 (G−1) 处的 5΄-鸟苷核苷和胞质 tRNAHis 受体茎顶部的 8 个核苷酸受体螺旋，其中 G−1–A73 错配，这是胞质 tRNA 物种中的特殊结构特征。虽然细胞质 tRNAHis 5΄-单磷酸的单甲基化既不影响体外的整体氨酰化过程，也不影响体内细胞质 tRNAHis 的稳态水平，但它可以保护细胞质 tRNAHis 转录物免于体外降解。因此，BCDIN3D充当细胞质tRNAHis特异性5'-甲基磷酸加帽酶。目前的结果还表明细胞质 tRNAHis 的 5΄-单磷酸的单甲基化和/或细胞质 tRNAHis 本身可能参与乳腺癌细胞的肿瘤发生。
Human RNA methyltransferase BCDIN3D is overexpressed in breast cancer cells, and is related to the tumorigenic phenotype and poor prognosis of breast cancer. Here, we show that cytoplasmic tRNAHis is the primary target of BCDIN3D in human cells. Recombinant human BCDIN3D, expressed in Escherichia coli, monomethylates the 5΄-monophosphate of cytoplasmic tRNAHis efficiently in vitro. In BCDN3D-knockout cells, established by CRISPR/Cas9 editing, the methyl moiety at the 5΄-monophosphate of cytoplasmic tRNAHis is lost, and the exogenous expression of BCDIN3D in the knockout cells restores the modification in cytoplasmic tRNAHis. BCIDN3D recognizes the 5΄-guanosine nucleoside at position −1 (G−1) and the eight-nucleotide acceptor helix with the G−1–A73 mis-pair at the top of the acceptor stem of cytoplasmic tRNAHis, which are exceptional structural features among cytoplasmic tRNA species. While the monomethylation of the 5΄-monophosphate of cytoplasmic tRNAHis affects neither the overall aminoacylation process in vitro nor the steady-state level of cytoplasmic tRNAHisin vivo, it protects the cytoplasmic tRNAHis transcript from degradation in vitro. Thus, BCDIN3D acts as a cytoplasmic tRNAHis-specific 5΄-methylphosphate capping enzyme. The present results also suggest the possible involvement of the monomethylation of the 5΄-monophosphate of cytoplasmic tRNAHis and/or cytoplasmic tRNAHis itself in the tumorigenesis of breast cancer cells.