Messenger RNA processing sites in Trypanosoma brucei
Messenger RNA processing sites in Trypanosoma brucei
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DOI：
10.1016/j.molbiopara.2005.05.008
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发表时间：
2005-10-01
影响因子：
1.5
通讯作者：
Guilbride, DL
中科院分区：
文献类型：
--
作者：
Benz, C;Nilsson, D;Guilbride, DL
在动质体中，蛋白质编码基因由RNA聚合酶II以多顺反子方式转录。通过39-nt加帽的前导RNA的5'反式剪接和3'聚腺苷酸化，从多顺反子前体产生各个成熟mRNA。先前已知反式剪接通常发生在多聚嘧啶段下游的AG二核苷酸处，并且多聚腺苷酸化与下游反式剪接偶联。已检查的少数多聚腺苷酸化位点是标记相邻反式剪接位点的多聚嘧啶段上游100-400 nt。通过扫描所有可用的布氏锥虫cDNA的剪接和多聚腺苷酸化位点，我们发现反式剪接通常发生在8-25 nt的多聚嘧啶段之后的第一个AG，产生中值长度为68 nt的5 '-UTR。我们还发现，在一般情况下，多聚腺苷酸化发生在一个位置与一个或多个A残基位于80和140核苷酸之间的下游聚嘧啶道。这些数据被用来校准的距离约束的语法模型中的自由参数，使锥虫基因组中的大多数蛋白质编码基因的多聚腺苷酸化和反式剪接位点的预测。来自基因组分析和程序的数据可从http://web.cgb.ki.se/daniel/splicemodel.php获得。(c)2005 Elsevier B. V.保留所有权利。
In Kinetoplastids, protein-coding genes are transcribed polycistronically by RNA polymerase II. Individual mature mRNAs are generated from polycistronic precursors by 5' trans splicing of a 39-nt capped leader RNA and 3' polyadenylation. It was previously known that trans splicing generally occurs at an AG dinucleotide downstream of a polypyrimidine tract, and that polyadenylation is coupled to downstream trans splicing. The few polyadenylation sites that had been examined were 100-400 nt upstream of the polypyrimidine tract which marked the adjacent trans splice site. We wished to define the sequence requirements for trypanosome mRNA processing more tightly and to generate a predictive algorithm.By scanning all available Trypanosoma brucei cDNAs for splicing and polyadenylation sites, we found that trans splicing generally occurs at the first AG following a polypyrimidine tract of 8-25 nt, giving rise to 5'-UTRs of a median length of 68 nt. We also found that in general, polyadenylation occurs at a position with one or more A residues located between 80 and 140 nt from the downstream polypyrimidine tract. These data were used to calibrate free parameters in a grammar model with distance constraints, enabling prediction of polyadenylation and trans splice sites for most protein-coding genes in the trypanosome genome. The data from the genome analysis and the program are available from: http://web.cgb.ki.se/daniel/splicemodel.php. (c) 2005 Elsevier B.V. All rights reserved.