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

我们分离出胎儿大脑富集的cDNA克隆，其相应的mRNA在胎儿大脑发育过程中优先表达，并分析其在人类脑肿瘤中的mRNA表达。通过差异筛选和cDNA减法程序，我们鉴定出22个不同的胎儿脑富集cDNA克隆，包括β -微管蛋白Mbeta5、β -微管蛋白Mbeta2、α -微管蛋白Malpha1、胸腺苷β a10、镇静素、神经蛋白、铁蛋白L链、α -间联素、两性蛋白、pi -激酶i型β、SAPAP-4、MARKS、MAZ和MN1。我们还分离了3个新克隆（FBE5、FBE88、FBE254）的全长cDNA，并分析了它们的编码蛋白。克隆FBE88编码一个新的转录调控蛋白，该蛋白属于Polycomb-group （PcG）基因，与果蝇致死性(3)恶性脑瘤肿瘤抑制基因有一定的相似性。在对分离的胎儿脑富集克隆对应的mRNA在各种人类肿瘤中的表达分析结果中，神经元蛋白mRNA的表达模式似乎值得注意。神经蛋白mRNA在人垂体腺瘤中选择性表达，并在几乎所有不表达功能激素的无功能腺瘤中大量表达，提示神经蛋白可能作为人垂体腺瘤新的肿瘤标志物。

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.