The monogenetic kinetoplastid protozoan, Crithidia fasciculata, contains a transcriptionally active, multicopy mini-exon sequence.
The monogenetic kinetoplastid protozoan, Crithidia fasciculata, contains a transcriptionally active, multicopy mini-exon sequence.
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单基因动质体原生动物 Crithidia fasciculata 含有转录活性的多拷贝迷你外显子序列。
DOI：
10.1093/nar/15.7.3141
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发表时间：
1987
影响因子：
14.9
通讯作者：
Simpson,L
中科院分区：
文献类型：
--
作者：
Muhich,ML;Hughes,DE;Simpson,AM;Simpson,L
从线虫束核基因组中分离到一个与其他动质原生动物的微小外显子基因同源的重复序列。序列分析证实，在该重复序列中存在一个35nT的序列，该序列与布鲁氏锥虫的35-聚体小外显子或剪接前导序列有77%的同源性。每个细胞大约有250个拷贝的重复序列，并被组织成一个或几个大的头尾串联簇，主要位于单个染色体上。微小外显子重复单位与一个主要的84个核苷酸和一个次要的87个核苷酸的聚(A)稳定状态转录本杂交，其中前35个核苷酸组成了在其他几个动质体种的mRNAs的5‘端发现的微型外显子序列。转录本的3‘末端位于DNA正义链上的位置上，直接位于8个胸苷残基之前。克里迪亚代表了最原始的动质体物种，显然具有不连续的mRNA加工类型，这意味着这可能代表着动质体原虫所有属的保守特征。
A repeated sequence from theCrithidia fasciculatanuclear genome has been isolated which is homologous to the mini-exon genes of other kinetoplastid protozoa. Sequence analysis of the 417 bp monomeric unit confirmed the presence of a 35 nt sequence within the repeat that is 77% homologous with theTrypanosoma brucei35-mer mini-exon or spliced leader sequence. The repeat is present at approximately 250 copies per cell and is organized into one, or a few, large head to tail tandem clusters predominantly on a single chromosome. The mini-exon repeat unit hybridizes to a major 84 nt and a minor 87 nt poly (A)- steady state transcript, the first 35 nts of which comprise the mini-exon sequence found at the 5' end of mRNAs in several other kinetoplastid species. The 3'-termini of the transcripts map to positions on the DNA sense strand directly preceeding a stretch of 8 thymidine residues.Crithidiarepresents the most primitive kinetoplastid species which apparently possesses a discontinuous type of mRNA processing, implying that this represents a conserved feature in possibly all genera of kinetoplastid protozoa.