Luthi-Carter R, Berger U V, Barczak A K, Enna M, Coyle J T
Department of Psychiatry, Massachusetts General Hospital-East, Charlestown, MA 02129, USA.
Proc Natl Acad Sci U S A. 1998 Mar 17;95(6):3215-20. doi: 10.1073/pnas.95.6.3215.
N-acetylated alpha-linked acidic dipeptidase (NAALADase) hydrolyzes acidic peptides, such as the abundant neuropeptide N-acetyl-alpha-L-aspartyl-L-glutamate (NAAG), thereby generating glutamate. Previous cDNA cloning efforts have identified a candidate rat brain NAALADase partial cDNA, and Northern analyses have identified a family of related RNA species that are found only in brain and other NAALADase-expressing cells. In this report, we describe the cloning of a set of rat brain cDNAs that describe a full-length NAALADase mRNA. Transient transfection of a full-length cDNA into the PC3 cell line confers NAAG-hydrolyzing activity that is sensitive to the NAALADase inhibitors quisqualic acid and 2-(phosphonomethyl)glutaric acid. Northern hybridization detects the expression of three similar brain RNAs approximately 3,900, 3,000, and 2,800 nucleotides in length. In situ hybridization histochemistry shows that NAALADase-related mRNAs have an uneven regional distribution in rat brain and are expressed predominantly by astrocytes as demonstrated by their colocalization with the astrocyte-specific marker glial fibrillary acidic protein.
N-乙酰化α-连接酸性二肽酶（NAALADase）可水解酸性肽，如含量丰富的神经肽N-乙酰-α-L-天冬氨酰-L-谷氨酸（NAAG），从而生成谷氨酸。先前的cDNA克隆研究已鉴定出一种候选大鼠脑NAALADase部分cDNA，Northern分析已鉴定出一组仅在脑和其他表达NAALADase的细胞中发现的相关RNA种类。在本报告中，我们描述了一组大鼠脑cDNA的克隆，这些cDNA描绘了一个全长NAALADase mRNA。将全长cDNA瞬时转染到PC3细胞系中可赋予对NAALADase抑制剂喹啉酸和2-（膦酰甲基）戊二酸敏感的NAAG水解活性。Northern杂交检测到三种长度约为3900、3000和2800个核苷酸的相似脑RNA的表达。原位杂交组织化学显示，NAALADase相关mRNA在大鼠脑中具有不均匀的区域分布，并且如通过它们与星形胶质细胞特异性标记物胶质纤维酸性蛋白的共定位所证明的，主要由星形胶质细胞表达。
