Winter N, Neumann A, Bullerdiek J
Center for Human Genetics, University of Bremen, Bremen, Germany.
Prenat Diagn. 2008 Dec;28(12):1126-30. doi: 10.1002/pd.2140.
The expression of the high mobility group protein gene HMGA2 is primarily confined to embryonic and fetal cells. The aim of this study was to determine the relative expression level of HMGA2 in cells of amniotic fluid samples. Furthermore, it should be investigated by chromatin immunoprecipitation whether or not HMGA2 is attached to cell-free DNA in amniotic fluid.
Expression levels of HMGA2 in 58 amniotic fluid samples from the second trimester were measured using quantitative real-time polymerase chain reaction (PCR). Furthermore, the presence of HMGA2, attached to cell-free DNA was tested by chromatin immunoprecipitation.
Expression of HMGA2 was detected in all samples, but in cells of the amniotic fluid it was 161-fold higher than in cells of the urine from healthy donors. The real-time PCR with GAPDH showed a signal in all samples treated with the improved protocol of immunoprecipitation.
Our data clearly show that cells of the amniotic fluid strongly overexpress HMGA2 according to their fetal origin. The fact that apparently HMGA2 remains to be attached to cell-free DNA suggests interesting new approaches in noninvasive prenatal diagnosis.
高迁移率族蛋白基因HMGA2的表达主要局限于胚胎和胎儿细胞。本研究的目的是确定羊水样本细胞中HMGA2的相对表达水平。此外，应通过染色质免疫沉淀法研究HMGA2是否附着于羊水中的游离DNA。
使用定量实时聚合酶链反应（PCR）测量来自孕中期的58份羊水样本中HMGA2的表达水平。此外，通过染色质免疫沉淀法检测附着于游离DNA的HMGA2的存在情况。
在所有样本中均检测到HMGA2的表达，但在羊水细胞中的表达比健康供体尿液细胞中的表达高161倍。用GAPDH进行的实时PCR在所有采用改进免疫沉淀方案处理的样本中均显示出信号。
我们的数据清楚地表明，羊水细胞因其胎儿来源而强烈过表达HMGA2。显然HMGA2仍附着于游离DNA这一事实提示了无创产前诊断中有趣的新方法。
