Exon scrambling of MLL transcripts occur commonly and mimic partial genomic duplication of the gene
Exon scrambling of MLL transcripts occur commonly and mimic partial genomic duplication of the gene
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DOI：
10.1016/s0378-1119(97)00640-9
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发表时间：
1998-02-27
期刊：
影响因子：
3.5
通讯作者：
Wiedemann, LM
中科院分区：
文献类型：
--
作者：
Caldas, C;So, CW;Wiedemann, LM
MLL基因在急性人白血病的髓系和淋巴系中经常重排。使用一个敏感的逆转录-聚合酶链反应（RT-PCR）测定，我们确定了几个异常剪接的成绩单中，MLL外显子加入的顺序不同的基因组方向（乱序外显子）。正常组织和恶性肿瘤组织中均存在MILL的错剪接。虽然这些乱序转录本中的大多数在共有剪接位点准确地连接，但有几个例子中，外显子以异常顺序剪接的接头在非共有位点。许多特征将MLL的错误剪接与先前描述的乱序外显子和环状RNA的情况区分开。一些乱序转录物似乎存在于RNA的多聚腺苷酸化部分中。没有相关的外显子打乱与外显子跳跃被发现，并没有特别的倾向，为外显子参与附近的大内含子。我们的数据表明，MLL的剪接是非常复杂的。在正常和白血病细胞中的乱序转录本的存在下，无法区分从基因组MLL重排产生的转录本，排除使用巢式RT-PCR作为检测MLL串联重复的筛选方法。(C)1998年Elsevier Science B.V.
The MLL gene is frequently rearranged in acute human leukemia of both the myeloid and lymphoid lineages. Using a sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) assay, we identified several abnormally spliced transcripts in which MLL exons were joined in an order different from the genomic orientation (scrambled exons). Mis-splicing of MILL was present in both normal and malignant tissues. Although the majority of these scrambled transcripts were joined accurately at consensus splice sites, there were several examples in which the junctions of exons spliced in aberrant order were at non-consensus sites. A number of features differentiate mis-splicing of MLL from the previously described cases of scrambled exons and circular RNAs. Some scrambled transcripts appear to be present in the polyadenylated fraction of RNA. No correlation of exon scrambling with exon skipping was found, and there was no particular tendency for the exons involved to be near large introns. Our data show that splicing of MLL is extremely complex. The presence of scrambled transcripts in both normal and leukemic cells, indistinguishable from transcripts resulting from genomic MLL rearrangements, precludes the use of nested RT-PCR as a screening method for detection of tandem duplication of MLL. (C) 1998 Elsevier Science B.V.