FIGURE 10-22 RNA editing of APOB pre-mRNA. The APOB mRNA produced in the liver has the same sequence as the exons in the primary transcript. This mRNA is translated into apoB-100, which has two functional domains: an N-terminal domain (green) that associates with lipids and a C-terminal domain (orange) that binds to LDL receptors on cell membranes. In the APOB mRNA produced in the intestine, however, the CAA codon in exon 26 is edited to a UAA stop codon. As a result, intestinal cells produce apoB-48, which corresponds to the N-terminal domain of apoB-100. See P. Hodges and J. Scott, 1992, Trends Biochem. Sci. 17:77.