Dente L, Pizza M G, Metspalu A, Cortese R
European Molecular Biology Laboratory, Heidelberg, FRG.
EMBO J. 1987 Aug;6(8):2289-96. doi: 10.1002/j.1460-2075.1987.tb02503.x.
alpha 1-acid glycoprotein (alpha AGP) is a well-characterized human plasma protein. Its structural properties have been studied for many years but little is known about its function. Amino acid sequence analysis of purified human alpha AGP from plasma pooled from several individuals showed considerable heterogeneity. We have cloned the genomic DNA segment encoding alpha AGP and we show that it contains three adjacent alpha AGP coding regions, AGP-A, B and B', identical in exon--intron organization but with slightly different coding potential. These results account for the heterogeneity observed by protein sequencing. Southern blot analysis indicates that the cloned cluster contains all the alpha AGP coding sequences present in the human genome. The larger majority of alpha AGP mRNA in human liver is transcribed from AGP-A, whose promoter and cap site have been determined while the level of AGP-B and B' mRNA in human liver is very low. Using Hep3B hepatoma cells as a model system for the in vitro study of the acute phase reaction, we show that only AGP-A is strongly induced by treatment with culture medium of LPS stimulated monocytes.
α1-酸性糖蛋白（αAGP）是一种已被充分表征的人血浆蛋白。其结构特性已研究多年，但对其功能了解甚少。对从多个个体混合血浆中纯化得到的人αAGP进行氨基酸序列分析，结果显示存在相当大的异质性。我们已经克隆了编码αAGP的基因组DNA片段，并表明它包含三个相邻的αAGP编码区，即AGP-A、B和B'，它们的外显子-内含子组织相同，但编码潜力略有不同。这些结果解释了蛋白质测序中观察到的异质性。Southern印迹分析表明，克隆的基因簇包含人类基因组中存在的所有αAGP编码序列。人肝脏中绝大多数αAGP mRNA是从AGP-A转录而来的，其启动子和帽位点已被确定，而人肝脏中AGP-B和B' mRNA的水平非常低。使用Hep3B肝癌细胞作为体外研究急性期反应的模型系统，我们发现只有AGP-A在用脂多糖刺激的单核细胞培养基处理后会被强烈诱导。
