急性T细胞白血病细胞变异型sil-tal1融合转录本和基因组DNA断裂点

Variant Fusion Transcripts and Genomic DNA Breakpoint of sil-tal1 in T-ALL Cells

本研究探究1例儿童急性T淋巴细胞白血病(T-ALL)的变异型sil-tal1融合转录本的序列。将PCR扩增产物克隆入质粒载体并测序,针对变异部分序列设计引物,对基因组DNA进行PCR扩增及序列比对。结果表明,在cDNA水平发现4种不同的融合转录本,分别保留了sil基因的部分外显子或内含子序列,并存在插入和删除现象。经分析白血病细胞的基因组DNA序列,发现了一种新的sil-tal1重组,其sil基因的断裂点在DNA水平上与文献报道不同。结论:此例患儿白血病细胞的tal1基因发生了新型重组,并表达经典型的和至少3种变异型的融合转录本,此现象可能是由于白血病细胞转录剪接机制异常所致。

The aim of this study was to investigate the nucleotide sequence of one distinct fusion transcript of sil-tal1 in childhood T-ALL.The PCR product was cloned into plasmid vector and then sequenced.Genomic DNA was analyzed with PCR using the designed primer pairs representing distinct sequences.The product was sequenced and analyzed with database.The results indicated that 4 different fusion transcripts were detected at cDNA level,in which a part of exons or introns of sil are reserved respectively,and some additions and deletions existed.After analyzing genomic DNA sequence of leukemic cells,the breakpoint in gene sil of this case was proved to be different at DNA level from references.Hence,the sil-tal1 rearrangement was defined to be a new type.It is concluded tal1 rearrangement of leukemic cells in this case is a new type,which expresses classical and at least 3 variant fusion transcripts,presumably caused by extraordinary mechanisms of splicing and transcription in leukemic stem cells.