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

我们分离了胎脑富集的cDNA克隆，其相应的mRNA在脑发育过程中在胎脑中优先表达，并分析了mRNA在人脑肿瘤中的表达。使用差异筛选和cDNA减法程序，我们确定了22个不同的胎脑富集的cDNA克隆，其中包括β-微管蛋白Mbeta 5，β-微管蛋白Mbeta 2，α-微管蛋白Malpha 1，胸腺素β 10，stathmin，神经元蛋白，铁蛋白L链，α-internexin，aperterin，PI-激酶II β型，SAPAP-4，MARKS，MAZ和MN 1。我们还分离了3个新克隆（FBE 5、FBE 88、FBE 254）的全长cDNA并分析了它们的编码蛋白。克隆FBE 88编码一种新的转录调控蛋白，属于Polycomb-组（PcG）基因，与果蝇肿瘤抑制基因致死性（3）恶性脑肿瘤有一定的相似性。在对应于各种人类肿瘤中分离的胎脑富集克隆的mRNA的表达分析结果中，神经元素mRNA的表达模式似乎值得注意。neuronatin mRNA在多种肿瘤组织中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可能作为垂体腺瘤的一种新的肿瘤标志物。

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.