RNA branching and debranching in the yeast retrovirus-like element Ty1
RNA branching and debranching in the yeast retrovirus-like element Ty1
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DOI：
10.1126/science.1087023
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发表时间：
2004-01-09
期刊：
影响因子：
56.9
通讯作者：
Menees, TM
中科院分区：
文献类型：
--
作者：
Cheng, Z;Menees, TM
酿酒酵母的Ty元件是与逆转录病毒相关的长末端重复序列（LTR）逆转录元件。正常水平的Ty 1转座需要Dbr 1 p，一种切割2 '-5' RNA键的细胞酶。我们发现，Ty 1 RNA缺乏可识别的5'端积累在病毒样颗粒（VLP）的dbr 1突变体。在体外用Dbr 1 p将该RNA脱支产生正常Ty 1 RNA 5'端的未加帽形式。我们发现Ty 1 RNA的5'核苷酸（nt）与同一RNA 3'端附近的nt形成2 '-5'键，形成套索。的性质表明，它的形式由一种新的机制，分支和脱支可能发挥作用，在Ty 1逆转录负链转移步骤。
Ty elements of Saccharomyces cerevisiae are long terminal repeat (LTR) retroelements related to retroviruses. Normal levels of Ty1 transposition require Dbr1p, a cellular enzyme that cleaves 2'-5' RNA bonds. We show that Ty1 RNAs lacking identifiable 5' ends accumulate in virus-like particles (VLPs) in dbr1 mutants. Debranching this RNA in vitro with Dbr1p creates an uncapped version of the normal Ty1 RNA 5' end. We show that the 5' nucleotide (nt) of Ty1 RNA forms a 2'-5' bond with a nt near the 3' end of the same RNA, creating a lariat. The properties of the lariat suggest it forms by a novel mechanism and that branching and debranching may play roles in Ty1 reverse transcription at the minus-strand transfer step.