The mechanism for apo-B mRNA editing is deamination.
Apolipoprotein (apo-) B mRNA editing at nucleotide 6666 converts cytidine to uridine, transforming the codon for glutamine-2153 to a termination codon. To investigate this editing mechanism, [a-32P] and [5-3H] CTP were incorporated into synthetic apo-B RNA. After the substrate had been edited extensively in vitro by a partially purified editing extract, the edited base was isolated and analyzed for radioactivity. The uridine-6666 resulting from the editing reaction had the same ratio of 3H to 32P as did the cytidine-6666, demonstrating that deamination rather than base exchange or nucleotide replacement is the mechanism for apo-B mRNA editing.
Johnson
D F
DF
Gladstone Institute of Cardiovascular Disease, University of California, San Francisco 94141-9100.
Poksay
K S
KS
Innerarity
T L
TL
D000818:Animals; D001055:Apolipoproteins B / Q000235:genetics*; D001483:Base Sequence; D002469:Cell Separation; D002474:Cell-Free System; D003562:Cytidine / Q000378:metabolism; D003641:Deamination; D004848:Epithelium / Q000378:metabolism; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism*; D008969:Molecular Sequence Data; D017393:RNA Editing; D011817:Rabbits; D014529:Uridine / Q000378:metabolism
D001055:Apolipoproteins B; D003562:Cytidine; D014529:Uridine