Apolipoprotein B is synthesized in selected human non-hepatic cell lines but not processed into mature lipoprotein.
Apolipoprotein B is synthesized in selected human non-hepatic cell lines but not processed into mature lipoprotein.
复制标题
载脂蛋白 B 在选定的人类非肝细胞系中合成，但不加工成成熟脂蛋白。
DOI：
10.1177/002215540205000504
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Phillips,ThomasE
中科院分区：
文献类型：
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作者：
Dixon,JosephL;Biddle,Jason;Lo,Chun-min;Stoops,JDaniel;Li,Hao;Sakata,Nobuhiro;Phillips,ThomasE
我们研究了载脂蛋白B100 （apoB）在一系列非肝细胞系（HT29结肠腺癌、HeLa宫颈上皮样癌和1321N1J星形细胞瘤人细胞系）和人肝癌细胞系HepG2中的代谢。逆转录聚合酶链反应检测ApoB mRNA在各非肝细胞系中的表达。采用免疫沉淀法、Western blotting法和免疫细胞化学方法检测HepG2细胞中ApoB的含量，采用多克隆抗人低密度脂蛋白（LDL）抗体、抗人载脂蛋白肽抗体和几种单克隆抗载脂蛋白ob抗体。用抗载脂蛋白ob肽和单克隆抗体在三种非肝细胞系中均能鉴定出载脂蛋白ob，但不能用抗ldl抗体鉴定。免疫细胞化学表明，载脂蛋白ob的表位在整个内质网中都很明显，新标记的载脂蛋白ob的凝胶流动性和抗泛素免疫印迹表明，载脂蛋白ob在非肝细胞中高度泛素化。观察到载脂蛋白ob在非肝细胞系中合成，但从未被抗ldl抗体识别，这表明载脂蛋白ob在这些细胞中没有加工成新生脂蛋白。载脂蛋白ob表位在非肝细胞的许多位置的免疫细胞化学定位提出了载脂蛋白ob在这些细胞中可用于其他目的的令人兴奋的可能性。
We studied apolipoprotein B100 (apoB) metabolism in a series of non-hepatic cell lines (HT29 colon adenocarcinoma, HeLa cervical epithelioid carcinoma, and 1321N1J astrocytoma human cell lines) and in the human hepatoma cell line HepG2. ApoB mRNA was detected by reverse transcription polymerase chain reaction in each non-hepatic cell line. ApoB was detected in HepG2 cells by immunoprecipitation, Western blotting, and immunocytochemistry using a polyclonal anti-human low-density lipoprotein (LDL) antibody, an anti-human apoB peptide antibody, and several monoclonal anti-apoB antibodies. ApoB was identified in the three non-hepatic cell lines by each method using the anti-apoB peptide and monoclonal antibodies, but not with the anti-LDL antibody. Im-munocytochemistry indicated that epitopes of apoB were evident throughout the endoplasmic reticulum, and gel mobility of newly labeled apoB and immunoblot with anti-ubiquitin showed that apoB was highly ubiquinated in non-hepatic cells. The observations that apoB is synthesized in non-hepatic cell lines but never recognized by the anti-LDL antibody suggests that apoB is not processed into a nascent lipoprotein in these cells. Immunocytochemical localization of apoB epitopes at many locations throughout non-hepatic cells raises the exciting possibility that apoB can be used for other purposes in these cells.