DMD基因内含子中的多种、多个重复顺序与外显子缺失关系的探讨

A study of the relationship between multiple and multiplex repeat sequences in introns and the deletion of exons of DMD gene

目的为探讨假肥大型肌营养不良症（ＤＭＤ）基因内含子的核苷酸序列特点与存在于内含子中的多个断裂点的关系。方法克隆了含ＤＭＤ基因第５０和５１号内含子的人基因组ＤＮＡ３．１ｋｂ－ＨｉｎｄⅢ片段，测出该片断的全顺序并用计算机分析序列特点。结果该ＤＮＡ片段的长度为３１７９ｂｐ，包含长１６４７ｂｐ的部分第５０号内含子和长１２９９ｂｐ的部分第５１号内含子以及第５１号外显子的全部２３３ｂｐ。在第５０和５１号内含子中发现３６个短串联重复顺序、２２个正向和反向重复顺序和８个同源顺序。结论多种、多个重复顺序的存在及这些重复顺序之间的重组可能导致的ＤＮＡ断裂，并造成第５１号外显子的缺失。

Objective The purpose of the study was to investigate the relationship between the character of nucleic acids and the multiple breakpoints in the introns of DMD gene. Method The 3.1kb HindⅢ human genome fragments containing the introns 50 and 51 were cloned and the sequencing character was analysed with a computer. Results The length of the fragment was 3 179 bp, including the 1 647 bp long intron 50 and the 1 299 bp long intron 51. There were 36 short tandom repeats, 22 direct and inverted repeats, and 8 homologous sequences in the introns 50 and 51. Conclusion Multiple and multiplex repeat sequences in the introns of DMD gene and the recombination of these repeat sequences might result in the DNA breaks and the deletion of the 51st exons.