Hoffer M J, van Eck M M, Havekes L M, Hofker M H, Frants R R
MGC-Department of Human Genetics, Leiden University, The Netherlands.
Genomics. 1993 Jul;17(1):45-51. doi: 10.1006/geno.1993.1281.
Three cDNA clones containing the mouse apolipoprotein C2 (Apoc2) gene were isolated from a mouse liver cDNA library. The inserts from two cDNA clones were 500 bp in size while the insert from the third clone was unexpectedly large, 962 bp. All three clones contained a single open reading frame encoding apoC2. The exon-intron structure of the mouse Apoc2 gene was determined by sequence analysis. Northern blotting and primer extension analysis of mouse RNA showed that the major liver transcript is 500 bp in size and is encoded by four exons. Transcripts for Apoc2 were found in fetal liver, adult liver, intestine, and peritoneal macrophages. The largest cDNA clone, mAPOC2c4, contained an additional 440 bp at the 5' end that are evolutionary conserved between man and mouse. These additional sequences are encoded by two exons located 5' to the major liver start site. Although the larger transcript could not be detected by Northern blot analysis, products resulting from an upstream transcription initiation site were detected in the liver using RT-PCR analysis. The sizes of the RT-PCR products are consistent with alternative splicing.
从一个小鼠肝脏cDNA文库中分离出了三个包含小鼠载脂蛋白C2（Apoc2）基因的cDNA克隆。两个cDNA克隆的插入片段大小为500 bp，而第三个克隆的插入片段出乎意料地大，为962 bp。所有三个克隆都包含一个编码载脂蛋白C2的单一开放阅读框。通过序列分析确定了小鼠Apoc2基因的外显子-内含子结构。对小鼠RNA的Northern印迹和引物延伸分析表明，主要的肝脏转录本大小为500 bp，由四个外显子编码。在胎儿肝脏、成年肝脏、肠道和腹膜巨噬细胞中发现了Apoc2的转录本。最大的cDNA克隆mAPOC2c4在5'端含有另外440 bp，这些序列在人和小鼠之间是进化保守的。这些额外的序列由位于主要肝脏起始位点5'端的两个外显子编码。尽管通过Northern印迹分析无法检测到较大的转录本，但使用RT-PCR分析在肝脏中检测到了上游转录起始位点产生的产物。RT-PCR产物的大小与可变剪接一致。
