Discontinuous transcription in Leptomonas seymouri: presence of intact and interrupted mini-exon gene families.
Discontinuous transcription in Leptomonas seymouri: presence of intact and interrupted mini-exon gene families.
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Leptomonas seymouri 中的不连续转录：完整和中断的迷你外显子基因家族的存在。
DOI：
10.1093/nar/16.15.7437
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发表时间：
1988
影响因子：
14.9
通讯作者：
Cross,GA
中科院分区：
文献类型：
--
作者：
Bellofatto,V;Cooper,R;Cross,GA
锥虫原生动物的成熟mRNA由至少两个外显子的连接产生，其最初转录为单独的RNA。在迄今为止检查的所有锥虫中，第一个外显子（小外显子）由大约200个串联重复基因编码。在表征小外显子基因的细单胞菌seymouri，我们确定了两个主要大小类的重复序列，杂交强烈的L。seymourimini-exon序列这两个序列被安排为散布的簇。代表较小大小类别的克隆的DNA序列分析表明，这些序列具有编码对应于在L的北方印迹中看到的86 nt组分的小外显子供体（med）RNA的能力。seymouriRNA。较大的类包括一个家族的相关序列，其中一些含有插入到medRNA基因的小外显子部分的DNA。此处鉴定的特异性插入片段（林斯1）仅与medRNA序列相关，并且存在于约20%的较大大小的L类中。seymourimedRNA基因。不考虑插入，smallerbona fidemini-exon基因的序列和包含插入的基因拷贝几乎相同。插入序列以与medRNA相同的方向转录，以产生至少四个小的非聚腺苷酸化RNA，其似乎不与medRNA序列连接。
Mature mRNAs of trypanosomatid protozoa result from the joining of at least two exons, which are initially transcribed as separate RNAs. In all trypanosomatids examined to date, the first exon (mini-exon) is encoded by approximately 200 tandemly reiterated genes. In characterizing the mini-exon genes ofLeptomonas seymouri, we identified two predominant size classes of repetitive sequences that hybridized strongly to theL. seymourimini-exon sequence. These two sequences are arranged as interspersed clusters. DNA sequence analysis of a clone representing the smaller size class demonstrated that these sequences have the capacity to encode a mini-exon donor (med)RNA corresponding to the 86 nt component seen in Northern blots ofL. seymouriRNA. The larger size class comprises a family of related sequences, some of which contain DNA inserted into the mini-exon portion of the medRNA gene. The specific insert identified here (LINS 1) is exclusively associated with medRNA sequences, and is present in approximately 20% of the larger size class ofL. seymourimedRNA genes. Disregarding the insertion, the sequences of the smallerbona fidemini-exon genes and the gene copy containing the insert were almost identical. The insert sequence is transcribed in the same direction as medRNA to yield at least four small non-polyadenylated RNAs, which appeared not to be linked to medRNA sequences.