The cloning and preliminarily functional analysis of the human neurotrimin gene  

作　　者：LIU Jin, LI Guangtao, PENG Xiaozhong, LIU Bingyan, YIN Bin, TAN Xinyu, FAN Ming, FAN Wenhong, QIANG Boqin & YUAN Jiangang National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, National Human Genome North Center, Beijing 100005, China Department of Neuro- biology, Institute of Basic Medical Science, 27 Taiping Road, Beijing 100850, China 

出　　处：《Science China(Life Sciences)》2004年第2期158-164,共7页中国科学（生命科学英文版）

基　　金：This work was supported by the National Program for Key Basic Research Project(G1998051002);the National High Technology Research and Development Program(2001 AA221041;2002BA711A01-03);the National Natural Science Foundation of China(Grant No.39830070).

摘　　要：Proteins of the immunoglobulin superfamily (IgSF) are involved in a variety of spe- cific cell-cell interactions in the developing nervous system. To identify and characterize new members of this protein family in human nervous system, we screen the human fetal brain cDNA library and isolate a full-length cDNA clone which contains a 1032 bp open reading frame en- coding a protein of 344 amino acids. Sequence analysis reveals that it is a glycoprotein com- prised of three C2-1ike immunoglobulin domains and is anchored to the plasma membrane via a post-translationally attached glycosyl-phosphatidylinositol (GPI) moiety. The protein shows high sequence similarity to the rat Ntm (97%), so we term it human neurotrimin (NTM). Northern blot analysis reveals that (HUMAN)NTM has three different transcripts with the length of 3.2 kb, 4.0 kb and 9.0 kb respectively. It has a wider expression pattern than that of (RAT) Ntm. Notably, the expression of NTM in fetal brain is higher than that in mature brain and is stronger in nervous tumors than that in normal brain tissues. We insert an HA epitope tag between the third Ig-like domain of NTM and the site of GPI attachment, then construct it into the eukaryotic expression vector pcDNA3.1+/Zeocin. The pcDNA3.1-HA-NTM is transfected into the Chinese Hamster Ovary (CHO) cells. The results demonstrate that HA-NTM is expressed on the surface of CHO cells and could strengthen the aggregation of CHO-NTM cells.Proteins of the immunoglobulin superfamily (IgSF) are involved in a variety of spe- cific cell-cell interactions in the developing nervous system. To identify and characterize new members of this protein family in human nervous system, we screen the human fetal brain cDNA library and isolate a full-length cDNA clone which contains a 1032 bp open reading frame en- coding a protein of 344 amino acids. Sequence analysis reveals that it is a glycoprotein com- prised of three C2-1ike immunoglobulin domains and is anchored to the plasma membrane via a post-translationally attached glycosyl-phosphatidylinositol (GPI) moiety. The protein shows high sequence similarity to the rat Ntm (97%), so we term it human neurotrimin (NTM). Northern blot analysis reveals that (HUMAN)NTM has three different transcripts with the length of 3.2 kb, 4.0 kb and 9.0 kb respectively. It has a wider expression pattern than that of (RAT) Ntm. Notably, the expression of NTM in fetal brain is higher than that in mature brain and is stronger in nervous tumors than that in normal brain tissues. We insert an HA epitope tag between the third Ig-like domain of NTM and the site of GPI attachment, then construct it into the eukaryotic expression vector pcDNA3.1+/Zeocin. The pcDNA3.1-HA-NTM is transfected into the Chinese Hamster Ovary (CHO) cells. The results demonstrate that HA-NTM is expressed on the surface of CHO cells and could strengthen the aggregation of CHO-NTM cells.

关 键 词：human neurotrimin (NTM) immunoglobulin superfamily (IgSF) GPI-ANCHOR neural cell adhesion molecules. 

分 类 号：Q78[生物学—分子生物学]