FIGURE 4.
Effect of APOBEC-1 mutations on apoB hypermutation in HepG2 cells. APOBEC-1 mutants encoded in adenovirus were expressed in HepG2 cells in the presence of ACF adenovirus and total RNAs were extracted after a 2-d viral exposure. ApoB mRNA was amplified by RT-PCR. (A) Normal editing at site 6666 was determined by primer extension assay and (B,C) representative hypermutation at sites 6802 and 6639 was determined, respectively. The editing or hypermutation levels were an average of triplicate samples determined by a PhosphorImager after primer extension and gel separation. The gel presentation was a combination from three separated gels under the same setting. (D) mRNA expression verification of mutant genes versus house keeping gene GAPDH: cDNA aliquots underwent semiquantitative PCR amplification in the presence of [α-32P]-dCTP and the abundance of each gene was determined according to their PCR product counts after separation with 6% polyacrylamide gel electrophoresis.