Byeon M K, Westerman M A, Maroulakou I G, Henderson K W, Suster S, Zhang X K, Papas T S, Vesely J, Willingham M C, Green J E, Schweinfest C W
Center for Molecular and Structural Biology, Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, USA.
Oncogene. 1996 Jan 18;12(2):387-96.
The protein product of the DRA gene, a gene whose expression is down-regulated in colon adenomas and adenocarcinomas, is a membrane glycoprotein and a member of a family of sulfate transporters. It is expressed in the intestinal tract (duodenum, ileum, cecum, distal colon), but not in the esophagus or stomach. DRA mRNA expression is restricted to the mucosal epithelium, and DRA protein expression is further limited to the columnar epithelial cells, particularly to the brush border. Consistent with its expression in the differentiated columnar epithelium of the adult human colon, DRA is first expressed in the midgut of developing mouse embryos at day 16.5, corresponding with the time of differentiation of the epithelium of the small intestine. A model for the structure of the DRA protein is proposed and its possible role in colon tumorigenesis is discussed.
DRA基因的蛋白质产物是一种膜糖蛋白,属于硫酸盐转运蛋白家族成员,该基因在结肠腺瘤和腺癌中的表达下调。它在肠道(十二指肠、回肠、盲肠、远端结肠)中表达,但在食管或胃中不表达。DRA mRNA表达局限于黏膜上皮,而DRA蛋白表达进一步局限于柱状上皮细胞,特别是刷状缘。与它在成年人类结肠分化的柱状上皮中的表达一致,DRA在发育中小鼠胚胎第16.5天的中肠中首次表达,这与小肠上皮分化的时间相对应。本文提出了DRA蛋白的结构模型,并讨论了其在结肠肿瘤发生中的可能作用。