肌色素上皮源性因子基因与黑色素瘤的发生相关

Muscle pigment epithelium-derived factor gene associating with tumorigenesis of B16 melanoma

目的 寻找与B16黑色素瘤发生相关的DNA序列或片段。方法 用 10 5条引物对B16黑色素瘤及其来源小鼠C57BL/ 6J基因组DNA进行随机扩增多态DNA分析 ,比较肿瘤组织及其相应正常组织的DNA指纹 ,对差异很明显的片段回收、克隆和测序 ,序列与GenBank数据库进行同源性分析。结果 10 5条引物中有 2 4条引物扩增出的条带在肿瘤组织与其相应正常组织间存在差异。在 6个差异很明显的回收DNA片段中 ,引物AB8 5扩增后所得差异片段B8 5 ,肿瘤组织中此片段缺失 ,该片段序列长 610bp ,与GenBank序列数据库中鼠肌色素上皮源性因子基因具有 99% ( 4 19/ 4 2 1)的同源性 ,与鼠肌色素上皮源性因子 (PEDF)mRNA的同源性为 10 0 % ( 2 13 / 2 13 ) ,可以认为该序列即为此基因。结论 黑色素瘤中存在PEDF基因缺失 ,提示PEDF基因与黑色素瘤发生相关。

Objective Random amplified polymorphic DNA (RAPD) analysis was used to detect the genomic variant in B16 melanoma, and to seek the tumor related DNA fragments. Methods Genomic DNA from B16 melanoma and C57BL/6J mouse normal tissues were amplified by RAPD with 105 random primers,the significantly different DNA fragments were isolated, cloned and sequenced. DNA sequences were analyzed with GenBank data. Results 24 of the 105 primers generated polymorphic profiles when the B16 melanoma RAPD profile was compared to that of its normal tissue DNA. By amplification of the primer AB8 5, a tumor band showing loss with respect to normal band was detected and this DNA fragment was designated as B8 5. B8 5 was a 610 bp fragment, the sequencing result of B8 5 showed 99% homology with muscle pigment epithelium derived factor (PEDF) gene, and 100% homology with muscle pigment epithelium derived factor mRNA. B8 5 was therefore regarded as PEDF gene. Conclusion Our result found that allelic losses exist in PEDF gene, and therefore suggest that PEDF is associated with tumorigenesis of B16 melanoma.