Practice question

Classic example of mammalian C-to-U editing occurs in apolipoprotein B messenger RNA in small intestine, converting glutamine codon CAA at codon two thousand one hundred fifty-three to stop codon UAA, yielding truncated ApoB48 protein of two thousand one hundred fifty-two amino acids versus full-length ApoB100 of four thousand five hundred thirty-six amino acids synthesized in liver. ApoB48 lacks low-density lipoprotein receptor binding domain, essential for chylomicron formation. Editing mediated by APOBEC1 cytidine deaminase and ACF cofactor recognizing mooring sequence eleven nucleotides downstream of target cytidine within editosome complex.