目的:研究在非小细胞肺癌及癌旁组织中ceacam1通过选择性拼接而产生的两种转录产物的调控机制.方法:将用PCR方法获得ceacam1基因中从内含子5至外显子8长1 606 bp DNA片段插入到真核表达载体pCMV中,构建成ceacam1迷你基因模型并与ptb基因共转染,用PCR法鉴定转染后的产物变化;根据外显子7序列设计的探针GAE(16-nt)及ACE(8-nt)进行凝胶阻滞分析实验.分离与探针结合的蛋白并进行质谱分析.结果:ptb 3种cDNA与ceacam1迷你基因共转染后,CEACAMlL表达水平下降,其中ptb 4对迷你基因的表达产物影响最大.仅转染迷你基因的细胞中ceacam1L在两条带中所占比例为76.7%,而与ptb 3种重组质粒共转染后,比例分别下降至58.3%、64.8%和54.0%.凝胶阻滞实验表明,探针GAE能与核蛋白结合,而ACE基本不能与核蛋白结合,与GAE结合的蛋白经质谱分析为PTB.结论:PTB过表达与ceacam1低表达有明显的相关性,拼接因子PTB参与ceacam1的选择性拼接.

[1] LAURIE N A, COMEGYS M M, CARREIRO M P. Carcinoembryonic antigen-related cell adhesion molecule 1a-4L suppression of rat hepatocellular carcinomas. 2005(23). doi:10.1158/0008-5472.CAN-04-2841
[2] BEAUCHEMIN N, DRABER P, DVEKSLER G. Redefined nomenclature for members of the carcinoembryonic antigen family. 1999(2). doi:10.1006/excr.1999.4610
[3] BAMBERGER A M, RIETHDORF L, NOLLAU P. Dysregulated expression of CD66a (BGP,C-CAM),an adhesion molecule of the CEA family in endometrial cancer. 1998
[4] OKEGAWA T, PONG R, LI Y. The role of cell adhesion molecule in cancer progression and its application in cancer therapy. 2004(2)
[5] KLEINERMAN D I, DINNEY C P N, ZHANG W W. Suppression of human bladder cancer growth by increased expression of C-CAM-1 gene in an orthotopic model, 1996
[6] LUO W, WOOD C G, EARLEY K. Suppression of tumorigenicity of breast cancer cells by an epithelial cell adhesion molecule (C-CAM 1):the adhesion and growth suppression are mediated by different domains. 1997. doi:10.1038/sj.onc.1200999
[7] KUNATH T, ORDONEZ-GARCIA C, TURBIDE C. Inhibition of colonic tumor cell growth by biliary glycoprotein, 1995
[8] ESTRERA V T, PHAN D, LUO W. The cytoplasmic domain of C-CAM1cell adhesion molecule is necessary and sufficient to suppress the tumorigenicity of prostate cancer cells. 1999. doi:10.1006/bbrc.1999.1443
[9] WANG L, LIN S H, WU W G. C-CAM1,a candidate tumor suppressor gene,is abnormally expressed in primary lung cancers, 2000
[10] DIGNAM J D. Preparation of extracts from higher eukaryotes. 1990. doi:10.1016/0076-6879(90)82017-V
[11] SORIA J C, LEE H Y, LEE J. Lack of PTEN expression in non-small cell lung cancer could be related to promoter methylation. 2002(5)
[12] JIN W, McCUTCHEON I E, FULLER G N. Fibroblast growth factor receptor-1 alpha-exon exclusion and polypyrimidine tract-binding protein in glioblastoma multiforme tumors. 2000(5)
[13] PEREZ I, LIN C H, MCAFEE J. Mutation of PTB binding sites causes misregulation of alternative 3′ splice site selection in vivo, 1997
[14] GOODING C, ROBERTS G C, SMITH C W J. Role of an inhibitory element and pyrimidine tract binding protein in repression of a regulated a-tropomyosin exon, 1998
[15] LOPEZ A J. Alternative splicing of pre-mRNA:developmental consequences and mechanisms of regulation. 1998(). doi:10.1146/annurev.genet.32.1.279
[16] JIN W, BI W, HUANG E S. Glioblastoma cell-specific expression of fibroblast growth factor receptor-1beta requires an intronic repressor of RNA splicing. 1999(2)