APOB（apolipoprotein B），癌症关联基因，基因ID：338，该基因产物是乳糜微粒和低密度脂蛋白的主要载脂蛋白它以两种主要亚型apoB-48和apoB-100存在于血浆中：前者仅在肠道合成，后者在肝脏合成apoB的肠型和肝型是由一个来自一个非常长的mRNA的单个基因编码的这两个亚型共用一个n-末端序列。较短的apob-48蛋白在残基2180（caa->；uaa）处的apob-100转录物经rna编辑后产生，导致终止密码子的产生和早期翻译终止。该基因或其调控区的突变可导致低β蛋白血症、正常甘油三脂血症、低β蛋白血症和由于配体缺陷的载脂蛋白B引起的高胆固醇血症、影响血浆胆固醇和载脂蛋白B水平的疾病。[由RefSeq提供，2008年7月]This gene product is the main apolipoprotein of chylomicrons and low density lipoproteins. It occurs in plasma as two main isoforms， apoB-48 and apoB-100: the former is synthesized exclusively in the gut and the latter in the liver. The intestinal and the hepatic forms of apoB are encoded by a single gene from a single， very long mRNA. The two isoforms share a common N-terminal sequence. The shorter apoB-48 protein is produced after RNA editing of the apoB-100 transcript at residue 2180 (CAA->UAA)， resulting in the creation of a stop codon， and early translation termination. Mutations in this gene or its regulator。