B48 is preferentially translated over B100 in cells with increased endogenous apo B mRNA.
We recently demonstrated that expression of BHMT in McArdle RH-7777 (McA-BHMT) cells increases apo B mRNA abundance, leading to parallel increases in apo B secretion. The ratio of unedited to edited apo B mRNA was unchanged by BHMT expression. Based on the observation that secretion of B48 is increased relative to B100 in McA-BHMT cells, current studies now include comparison of B48 and B100 synthesis and intracellular degradation. Minor differences in co- and posttranslational degradation were unable to account for relative increase in B48 secretion, and the disappearance kinetics of B48 were similar in McA-BHMT and control cells. Consistent with the increase in endogenous apo B mRNA in McA-BHMT cells, B48 synthesis is increased significantly. In contrast, synthesis of B100 was not significantly increased. We conclude that B48 is preferentially translated compared to B100 when endogenous apo B mRNA is increased.
Collins
H L
HL
Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
Sparks
C E
CE
Sparks
J D
JD
D000818:Animals; D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B / Q000235:genetics*; D050940:Betaine-Homocysteine S-Methyltransferase; D002460:Cell Line; D008780:Methyltransferases / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats
D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B; D012333:RNA, Messenger; D008780:Methyltransferases; D050940:Betaine-Homocysteine S-Methyltransferase; C494550:Bhmt protein, rat