Isolation of the fetal brain-enriched cDNA clones and analysis of their corresponding mRNAs expressed in human brain tumors.

我们分离了在人脑发育过程中其相应的mRNAs在胎脑中优先表达的胎脑富集型cDNA克隆，并对其在人脑肿瘤中的表达进行了分析。利用差异筛选和cDNA消减技术，我们鉴定了22个不同的胎脑富集基因克隆，包括β-微管蛋白Mbeta5、β-微管蛋白Mbeta2、α-微管蛋白Malpha1、胸腺素Beta10、Stathmin、神经元抑素、铁蛋白L链、α-Interexin、两性蛋白、PI-激酶IIbeta、SAPAP-4、MARKS、MAZ和MN1。我们还分离了3个新克隆(FBE5、FBE88、FBE254)的全长cDNA，并对其编码蛋白进行了分析。克隆FBE88编码一种新的转录调控蛋白，属于多梳基因(PcG)，与果蝇的肿瘤抑制基因--致死性(3)恶性脑瘤有一定的相似性。在对分离的胎儿脑富集性克隆在各种人类肿瘤中对应的mRNAs的表达分析结果中，Neuronatin mRNA的表达模式似乎值得注意。在人类各种肿瘤组织中，Neuronatin mRNA有选择性地表达于垂体腺瘤中，并且在几乎所有不表达功能性激素的无功能腺瘤中大量表达，提示Neuronatin有可能作为一种新的肿瘤标志物应用于人类垂体腺瘤。

We isolated the fetal brain-enriched cDNA clones whose corresponding mRNAs were expressed preferentially in the fetal brain during the brain development, and analyzed the mRNA expression in the human brain tumors. Using the differential screening and cDNA subtraction procedures, we identified 22 distinct fetal brain-enriched cDNA clones which included beta-tubulin Mbeta5, beta-tubulin Mbeta2, alpha-tubulin Malpha1, thymosin beta10, stathmin, neuronatin, ferritin L chain, alpha-internexin, amphoterin, PI-kinase type IIbeta, SAPAP-4, MARKS,MAZ,and MN1. We also isolated the full length cDNA of 3 novel clones (FBE5, FBE88, FBE254) and analyzed their coding proteins. The clone FBE88 revealed to encode a novel transcriptional regulatory protein which belonged to Polycomb-group (PcG) genes and showed some similarity to a Drosophila tumor suppressor gene, lethal (3) malignant brain tumor. Among the results of the expression analyzes of the mRNAs corresponding to the isolated fetal brain-enriched clones in various human tumors, the expression pattern of the neuronatin mRNA seemed noteworthy. The neuronatin mRNA was expressed selectively in human pituitary adenomas among various human tumor tissues and abundantly in almost all non-functioning adenomas which express no functional hormones, suggesting the possible utility of the neuronatin as a new tumor marker of the human pituitary adenomas.