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目的通过比较唐氏综合征(DS)和正常胎儿大脑皮质中的基因差别表达模式,初步筛选出与 DS 大脑皮质发育异常、乃至与智力低下发生密切相关的人类21号染色体基因(HC21),为搭建21三体(T21)智力低下发生的分子网络奠定基础。方法利用 Affymetrix U133A 基因芯片分析HC21基因在20周 DS 和正常胎儿大脑皮质中的差别表达模式,利用半定量 RT-PCR 和反向 Northern印迹杂交对筛选出的 HC21基因进行鉴定。结果 Affymetrix U133A 芯片含有127个已知的 HC21基因,其中在两类大脑皮质中均不表达的有56个。在两类组织中均表达的71个 HC21基因中,表达上调1.4倍以上的 HC21基因有27个,表达下调1.5倍以上的有两个。对99个 HC21基因所进行的半定量 RT-PCR 和/或反向 Northern 印迹杂交分析也得到了一致的结果。结论在 DS 和正常胎儿脑组织中差别表达的 HC21基因可能就是造成 DS 脑组织结构和功能发育异常的根本原因,也是引发智力低下的重要的候选基因,对这些基因分子作用通路的深入研究是全面揭示 DS 胎儿大脑皮质发育异常乃至智力低下发生分子机制的基础。
OBJECTIVE: To compare the expression pattern of genes in Down’s syndrome (DS) and normal fetal cerebral cortex, to screen human chromosome 21 (HC21) closely related to dementia of cerebral cortex and even impaired intelligence, Set up 21 trisomy (T21) mental retardation molecular network laid the foundation. Methods Affymetrix U133A microarray was used to analyze the differential expression pattern of HC21 gene in 20-week DS and normal fetal cerebral cortex. Semi-quantitative RT-PCR and reverse Northern blot were used to identify the HC21 gene. Results The Affymetrix U133A chip contains 127 known HC21 genes, 56 of which are not expressed in both types of cerebral cortex. Of the 71 HC21 genes expressed in both tissues, there were 27 HC21 genes that were up-regulated more than 1.4-fold and two more than 1.5-fold down-regulated genes. Similar results were obtained with semi-quantitative RT-PCR and / or reverse Northern blot analysis of 99 HC21 genes. Conclusions The HC21 gene differentially expressed in DS and normal fetal brain tissue may be the underlying cause of structural abnormalities in brain function and dysfunction in DS. It is also an important candidate gene that causes mental retardation. The thorough study on the role of these genes in molecular pathways is comprehensive Reveal the basis of the molecular mechanism of DS fetal cerebral cortex dysplasia and even mental retardation.