论文部分内容阅读
目的检测正常人及视网膜母细胞瘤（ＲＢ）患者Ｒｂ基因５′端调控区的ＤＮＡ序列，以及不同的ＤＮＡ片段的转录调控活性，研究Ｒｂ基因启动子的结构、功能以及突变对功能的影响和与ＲＢ发病的关系。方法应用ＳＳＣＰ分析及ＤＮＡ序列测定检测正常人及ＲＢ患者Ｒｂ基因启动子的ＤＮＡ序列和点突变；分离Ｒｂ基因５′端不同位置及不同大小的ＤＮＡ片段，通过氯霉素乙酰基转移酶做报告基因，检测不同的ＤＮＡ片段的转录调控活性。结果Ｒｂ基因产物起始密码上游３２７ｂｐ至８７ｂｐ间２４０ｂｐ的ＤＮＡ片段具有基本的启动子功能，其上游和下游的ＤＮＡ序列内可能还存在正或负转录调控元件。１００例正常人Ｒｂ基因启动子ＤＮＡ序列未见有任何变异，但３０２例ＲＢ患者中５例有点突变并伴有ＣＡＴ活性明显降低。结论Ｒｂ基因启动子的ＤＮＡ序列非常稳定，其突变常常导致启动子活性下降，并与视网膜母细胞瘤的遗传易感性有关
OBJECTIVE: To detect the DNA sequence of the 5’regulatory region of Rb gene in normal human and retinoblastoma (RB) patients and the transcriptional regulatory activities of different DNA fragments. To study the effect of Rb gene promoter structure, function and mutation on function and And the incidence of RB. Methods The DNA sequence and point mutation of Rb gene promoter in normal and RB patients were detected by SSCP analysis and DNA sequencing. DNA fragments of different positions and sizes at the 5 ’end of Rb gene were isolated and reported by chloramphenicol acetyltransferase Genes that detect the transcriptional regulatory activity of different DNA fragments. Results The DNA fragment of 240bp between 327bp and 87bp upstream of the start codon of Rb gene product had basic promoter function, and positive or negative transcriptional regulatory elements might exist in its upstream and downstream DNA sequences. No mutation was found in the DNA sequence of Rb gene promoter in 100 cases of normal people. However, 5 cases of 302 patients with RB were slightly mutated and CAT activity was significantly decreased. Conclusion The DNA sequence of Rb gene promoter is very stable. The mutation often leads to the decrease of promoter activity and the genetic susceptibility to retinoblastoma