PolyQ重复变异对ATXN1基因转录的影响

A variable polyglutamine repeat affects the transcription of the ATXN1 gene

目的探讨ATXN1基因内PolyQ重复变异对ATXN1基因自身转录的影响。方法通过分子克隆构建正常ATXN1基因(PolyQ重复数为29)和突变ATXN1基因(PolyQ重复数为61),将其分别插入慢病毒载体pLVX-Puro-3xflag-C中构建表达载体,然后将携带正常和突变ATXN1基因的慢病毒表达载体分别感染人胚肾细胞(293T细胞),通过实时荧光定量PCR检测正常和突变ATXN1 mRNA的表达水平。结果293T细胞内正常和突变ATXN1 mRNA的相对表达量分别为(661.9±17.7)和(381.0±20.5),正常ATXN1 mRNA的相对表达量高于突变ATXN1 mRNA的相对表达量(P<0.05)。结论ATXN1基因内PolyQ重复变异可抑制ATXN1基因自身转录,对基因转录影响可能是PolyQ重复变异引起Ⅰ型脊髓小脑型共济失调的病理机制之一。

Objective To explore the effects of a variable polyglutamine repeat on the ATXN1 gene transcription.Methods Wild-type ATXN1(29Q)and mutant ATXN1(61Q)genes were constructed by molecular cloning.The expression vectors were generated by inserting wild-type and mutant ATXN1 genes into the pLVX-Puro-3xflag-C vector.Lentiviruses were generated by infecting the expression vectors into human embryonic kidney 293T cells.The expression levels of wild-type and mutant ATXN1 mRNA in 293T cells were detected by a real-time RTpolymerase chain reaction.Results The relative levels were(661.9±17.7)and(381.0±20.5)for wild-type and mutant ATXN1 mRNA in 293T cells,respectively.The relative level of wild-type ATXN1 mRNA was higher than that of mutant ATXN1 mRNA(P<0.05).Conclusion The variable polyglutamine repeat in the ATXN1 gene can inhibit the ATXN1 gene transcription,thus may contribute to spinocerebellar ataxia type 1.