A reverse transcriptase/maturase promotes splicing by binding at its own coding segment in a group II intron RNA
A reverse transcriptase/maturase promotes splicing by binding at its own coding segment in a group II intron RNA
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DOI：
10.1016/s1097-2765(00)80371-8
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发表时间：
1999-08-01
期刊：
影响因子：
16
通讯作者：
Lambowitz, AM
中科院分区：
文献类型：
--
作者：
Wank, H;SanFilippo, J;Lambowitz, AM
II 组内含子编码促进 RNA 剪接（成熟酶活性）的逆转录酶，然后与切除的内含子形成 DNA 核酸内切酶，通过目标 DNA 引发的逆转录 (TPRT) 介导内含子移动性。在这里，我们表明由乳酸乳球菌 Ll.LtrB 内含子编码的成熟酶 (LtrA) 的主要结合位点位于内含子结构域 IV 的区域内，该区域包括 LtrA ORF 的起始密码子。这种结合通过其他元件增强，特别是结构域 I 和 EBS/IBS 相互作用，并有助于定位 LtrA 以启动 3' 外显子中的 cDNA 合成，如 TPRT 期间发生的那样。我们的结果表明成熟酶如何在RNA剪接中发挥作用，并支持逆转录酶编码区源自插入预先存在的II组内含子中的独立遗传元件的假设。
Group II introns encode reverse transcriptases that promote RNA splicing (maturase activity) and then with the excised intron form a DNA endonuclease that mediates intron mobility by target DNA-primed reverse transcription (TPRT). Here, we show that the primary binding site for the maturase (LtrA) encoded by the Lactococcus lactis Ll.LtrB intron is within a region of intron domain IV that includes the start codon of the LtrA ORF. This binding is enhanced by other elements, particularly domain I and the EBS/IBS interactions, and helps position LtrA to initiate cDNA synthesis in the 3' exon as occurs during TPRT. Our results suggest how the maturase functions in RNA splicing and support the hypothesis that the reverse transcriptase coding region was derived from an independent genetic element that was inserted into a preexisting group II intron.