编码载脂蛋白H（β2-糖蛋白I）的人类基因的核苷酸序列及表达

Nucleotide sequence and expression of the human gene encoding apolipoprotein H (beta 2-glycoprotein I).

作者信息

Mehdi H, Nunn M, Steel D M, Whitehead A S, Perez M, Walker L, Peeples M E

机构信息

Department of Immunology/Microbiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612.

出版信息

Gene. 1991 Dec 15;108(2):293-8. doi: 10.1016/0378-1119(91)90449-l.

DOI:10.1016/0378-1119(91)90449-l

PMID:1748314

Abstract

Human apolipoprotein H (ApoH), also called beta 2-glycoprotein I, is a 50-kDa serum glycoprotein whose function is not clearly defined. We have cloned and sequenced ApoH cDNAs both from human liver and from a human hepatoma cell line (HepG2). Both cDNA sequences predict a protein 345 amino acids (aa) in length. This sequence includes a 19-aa hydrophobic, N-terminal signal sequence which is not present in the mature protein [Lozier et al., Proc. Natl. Acad. Sci. USA 81 (1984) 3640-3644]. It differs from this previously reported aa sequence at two positions, both of which strengthen the conservation among the four short consensus repeats within the ApoH molecule. COS-1 cells transiently transfected with the ApoH cDNA in a eukaryotic expression vector produced a single species of ApoH mRNA and secreted in the ApoH protein. The level of ApoH mRNA expressed by HepG2 cells is downregulated by incubation with inflammatory mediators, implying that ApoH is a negative acute-phase protein.

摘要

人载脂蛋白H（ApoH），也称为β2-糖蛋白I，是一种50 kDa的血清糖蛋白，其功能尚未明确界定。我们已经从人肝脏和人肝癌细胞系（HepG2）中克隆并测序了ApoH cDNA。两种cDNA序列均预测编码一种长度为345个氨基酸（aa）的蛋白质。该序列包括一个19个氨基酸的疏水N端信号序列，成熟蛋白中不存在该序列[洛齐尔等人，《美国国家科学院院刊》81 (1984) 3640 - 3644]。它在两个位置与先前报道的氨基酸序列不同，这两个位置都加强了ApoH分子内四个短共有重复序列之间的保守性。用真核表达载体中的ApoH cDNA瞬时转染COS - 1细胞，产生了单一类型的ApoH mRNA，并分泌了ApoH蛋白。用炎症介质孵育后，HepG2细胞表达的ApoH mRNA水平下调，这意味着ApoH是一种负急性期蛋白。