Effect of sucrose diet on expression of apolipoprotein genes A-I, C-III and A-IV in rat liver.
A sucrose-rich diet stimulates hepatic lipogenesis and induces net production of very low density lipoproteins in the liver. To study changes of hepatic apolipoprotein gene expression in response to such a diet, we measured the mRNA abundance of apolipoproteins A-I, C-III and A-IV in livers of rats fed a sucrose-rich diet or a control diet for 3 weeks. In livers of sucrose-fed rats, the abundance of cellular and nuclear apo A-IV mRNA increased to 185% +/- 21% and 142% +/- 22% of control values (P less than 0.01), respectively. In sucrose-fed rats, the transcriptional activity of the apo A-IV gene, measured in a cell-free transcription system using isolated liver nuclei, increased to 144% +/- 23% of control (P less than 0.05). In contrast, this diet neither affected the abundance of cellular and nuclear apo A-I and apo C-III mRNA nor the transcriptional activity of these genes in liver. These results are consistent with specialization of the regulatory elements of the genes coding for apolipoproteins A-I, C-III and A-IV. Alternatively, enhanced transcription of the apo A-IV gene may preclude increased synthesis of apo A-I and/or apo C-III mRNA due to the close linkage of the three genes in the rat genome.
Radosavljevic
M
M
Department of Medicine, Baylor College of Medicine, Houston, TX 77030.
Lin-Lee
Y C
YC
Soyal
S M
SM
Strobl
W
W
Seelos
C
C
Gotto
A M
AM
Patsch
W
W
D000818:Animals; D016632:Apolipoprotein A-I / Q000235:genetics*; D053305:Apolipoprotein C-III; D001054:Apolipoproteins A / Q000235:genetics*; D001056:Apolipoproteins C / Q000235:genetics*; D001483:Base Sequence; D004032:Diet; D015870:Gene Expression / Q000187:drug effects*; D008099:Liver / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013395:Sucrose / Q000008:administration & dosage* / Q000494:pharmacology; D014158:Transcription, Genetic
D016632:Apolipoprotein A-I; D053305:Apolipoprotein C-III; D001054:Apolipoproteins A; D001056:Apolipoproteins C; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; C022205:apolipoprotein A-IV; D013395:Sucrose