Abstract
Apolipoprotein B (apoB) is the major protein of plasma very low density lipoprotein (VLDL) and low density lipoprotein (LDL). Here we report the molecular cloning of cDNAs for rabbit liver apoB, by use of the expression vector lambda gt11, and the use of these cDNAs to study the regulation of apoB mRNA levels by dietary cholesterol. The beta-galactosidase-apoB fusion proteins expressed by recombinant clones were identified with guinea pig anti-rabbit LDL antibodies. The cloned cDNAs hybridized to an 18-kilobase mRNA that was present in liver and intestine. Slot blot analysis showed that this mRNA was not present in other tissues studied, with the possible exception of kidney. When rabbits are fed a high-cholesterol diet, they develop severe hypercholesterolemia. Most of the excess cholesterol is contained in beta-VLDL, a cholesteryl ester-rich lipoprotein that contains apoB and apoE. We addressed the question of whether increased apoB mRNA levels, and by inference increased apoB synthetic rates, are responsible for the accumulation of beta-VLDL. A comparison of apoB mRNA levels showed that cholesterol-fed rabbits had lower liver apoB mRNA levels than control rabbits. We suggest that the accumulation of plasma beta-VLDL in cholesterol-fed rabbits is not due to an increased production of beta-VLDL but solely due to a suppression of hepatic LDL receptors.
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- Blue M. L., Protter A. A., Williams D. L. Biosynthesis of apolipoprotein B in rooster kidney, intestine, and liver. J Biol Chem. 1980 Nov 10;255(21):10048–10051. [PubMed] [Google Scholar]
- Chait A., Albers J. J., Brunzell J. D. Very low density lipoprotein overproduction in genetic forms of hypertriglyceridaemia. Eur J Clin Invest. 1980 Feb;10(1):17–22. doi: 10.1111/j.1365-2362.1980.tb00004.x. [DOI] [PubMed] [Google Scholar]
- Chao Y. S., Yamin T. T., Thompson G. M., Kroon P. A. Tissue-specific expression of genes encoding apolipoprotein E and apolipoprotein A-I in rabbits. J Biol Chem. 1984 Apr 25;259(8):5306–5309. [PubMed] [Google Scholar]
- Chao Y., Yamin T. T., Alberts A. W. Effects of cholestyramine on low density lipoprotein binding sites on liver membranes from rabbits with endogenous hypercholesterolemia induced by a wheat starch-casein diet. J Biol Chem. 1982 Apr 10;257(7):3623–3627. [PubMed] [Google Scholar]
- Chirgwin J. M., Przybyla A. E., MacDonald R. J., Rutter W. J. Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease. Biochemistry. 1979 Nov 27;18(24):5294–5299. doi: 10.1021/bi00591a005. [DOI] [PubMed] [Google Scholar]
- Deeb S. S., Motulsky A. G., Albers J. J. A partial cDNA clone for human apolipoprotein B. Proc Natl Acad Sci U S A. 1985 Aug;82(15):4983–4986. doi: 10.1073/pnas.82.15.4983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Elovson J., Jacobs J. C., Schumaker V. N., Puppione D. L. Molecular weights of apoprotein B obtained from human low-density lipoprotein (apoprotein B-PI) and from rat very low density lipoprotein (apoprotein B-PIII). Biochemistry. 1985 Mar 12;24(6):1569–1578. doi: 10.1021/bi00327a042. [DOI] [PubMed] [Google Scholar]
- Gubler U., Hoffman B. J. A simple and very efficient method for generating cDNA libraries. Gene. 1983 Nov;25(2-3):263–269. doi: 10.1016/0378-1119(83)90230-5. [DOI] [PubMed] [Google Scholar]
- Hall L., Craig R. K., Campbell P. N. mRNA species directing synthesis of milk proteins in normal and tumour tissue from human mammary gland. Nature. 1979 Jan 4;277(5691):54–56. doi: 10.1038/277054a0. [DOI] [PubMed] [Google Scholar]
- Huang L. S., Bock S. C., Feinstein S. I., Breslow J. L. Human apolipoprotein B cDNA clone isolation and demonstration that liver apolipoprotein B mRNA is 22 kilobases in length. Proc Natl Acad Sci U S A. 1985 Oct;82(20):6825–6829. doi: 10.1073/pnas.82.20.6825. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Huff M. W., Carroll K. K. Effects of dietary protein on turnover, oxidation, and absorption of cholesterol, and on steroid excretion in rabbits. J Lipid Res. 1980 Jul;21(5):546–548. [PubMed] [Google Scholar]
- Janus E. D., Nicoll A. M., Turner P. R., Magill P., Lewis B. Kinetic bases of the primary hyperlipidaemias: studies of apolipoprotein B turnover in genetically defined subjects. Eur J Clin Invest. 1980 Apr;10(2 Pt 1):161–172. doi: 10.1111/j.1365-2362.1980.tb02076.x. [DOI] [PubMed] [Google Scholar]
- Kane J. P. Apolipoprotein B: structural and metabolic heterogeneity. Annu Rev Physiol. 1983;45:637–650. doi: 10.1146/annurev.ph.45.030183.003225. [DOI] [PubMed] [Google Scholar]
- Kane J. P., Hardman D. A., Paulus H. E. Heterogeneity of apolipoprotein B: isolation of a new species from human chylomicrons. Proc Natl Acad Sci U S A. 1980 May;77(5):2465–2469. doi: 10.1073/pnas.77.5.2465. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kissebah A. H., Alfarsi S., Adams P. W. Integrated regulation of very low density lipoprotein triglyceride and apolipoprotein-B kinetics in man: normolipemic subjects, familial hypertriglyceridemia and familial combined hyperlipidemia. Metabolism. 1981 Sep;30(9):856–868. doi: 10.1016/0026-0495(81)90064-0. [DOI] [PubMed] [Google Scholar]
- Knott T. J., Rall S. C., Jr, Innerarity T. L., Jacobson S. F., Urdea M. S., Levy-Wilson B., Powell L. M., Pease R. J., Eddy R., Nakai H. Human apolipoprotein B: structure of carboxyl-terminal domains, sites of gene expression, and chromosomal localization. Science. 1985 Oct 4;230(4721):37–43. doi: 10.1126/science.2994225. [DOI] [PubMed] [Google Scholar]
- Kovanen P. T., Brown M. S., Basu S. K., Bilheimer D. W., Goldstein J. L. Saturation and suppression of hepatic lipoprotein receptors: a mechanism for the hypercholesterolemia of cholesterol-fed rabbits. Proc Natl Acad Sci U S A. 1981 Mar;78(3):1396–1400. doi: 10.1073/pnas.78.3.1396. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kritchevsky D., Tepper S. A., Williams D. E., Story J. A. Experimental atherosclerosis in rabbits fed cholesterol-free diets. Part 7. Interaction of animal or vegetable protein with fiber. Atherosclerosis. 1977 Apr;26(4):397–403. doi: 10.1016/0021-9150(77)90110-1. [DOI] [PubMed] [Google Scholar]
- Kroon P. A., Hand K. M., Huff J. W., Alberts A. W. The effects of mevinolin on serum cholesterol levels of rabbits with endogenous hypercholesterolemia. Atherosclerosis. 1982 Jul;44(1):41–48. doi: 10.1016/0021-9150(82)90051-x. [DOI] [PubMed] [Google Scholar]
- Kroon P. A., Seidenberg J. Organization of the core lipids of lipoproteins from normal and cholesterol-fed rabbits. A proton nuclear magnetic resonance study. Biochemistry. 1982 Dec 7;21(25):6483–6488. doi: 10.1021/bi00268a025. [DOI] [PubMed] [Google Scholar]
- Kroon P. A., Thompson G. M., Chao Y. S. A comparison of the low-density-lipoprotein receptor from bovine adrenal cortex, rabbit and rat liver and adrenal glands by lipoprotein blotting. Biochem J. 1984 Oct 15;223(2):329–335. doi: 10.1042/bj2230329. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kroon P. A., Thompson G. M., Chao Y. S. Beta-very low density lipoproteins in cholesterol-fed rabbits are of hepatic origin. Atherosclerosis. 1985 Sep;56(3):323–329. doi: 10.1016/0021-9150(85)90007-3. [DOI] [PubMed] [Google Scholar]
- Lee D. M., Koren E., Singh S., Mok T. Presence of B-100 in rat mesenteric chyle. Biochem Biophys Res Commun. 1984 Sep 28;123(3):1149–1156. doi: 10.1016/s0006-291x(84)80253-3. [DOI] [PubMed] [Google Scholar]
- Lusis A. J., West R., Mehrabian M., Reuben M. A., LeBoeuf R. C., Kaptein J. S., Johnson D. F., Schumaker V. N., Yuhasz M. P., Schotz M. C. Cloning and expression of apolipoprotein B, the major protein of low and very low density lipoproteins. Proc Natl Acad Sci U S A. 1985 Jul;82(14):4597–4601. doi: 10.1073/pnas.82.14.4597. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MacKinnon A. M., Savage J., Gibson R. A., Barter P. J. Secretion of cholesteryl ester-enriched very low density lipoproteins by the liver of cholesterol-fed rabbits. Atherosclerosis. 1985 Feb;54(2):145–155. doi: 10.1016/0021-9150(85)90174-1. [DOI] [PubMed] [Google Scholar]
- Mehrabian M., Schumaker V. N., Fareed G. C., West R., Johnson D. F., Kirchgessner T., Lin H. C., Wang X. B., Ma Y. H., Mendiaz E. Human apolipoprotein B: identification of cDNA clones and characterization of mRNA. Nucleic Acids Res. 1985 Oct 11;13(19):6937–6953. doi: 10.1093/nar/13.19.6937. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Okayama H., Berg P. High-efficiency cloning of full-length cDNA. Mol Cell Biol. 1982 Feb;2(2):161–170. doi: 10.1128/mcb.2.2.161. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Richman D. D., Cleveland P. H., Oxman M. N., Johnson K. M. The binding of staphylococcal protein A by the sera of different animal species. J Immunol. 1982 May;128(5):2300–2305. [PubMed] [Google Scholar]
- Thompson K. H., Zilversmit D. B. Plasma very low density lipoprotein (VLDL) in cholesterol-fed rabbits: chylomicron remnants or liver lipoproteins? J Nutr. 1983 Oct;113(10):2002–2010. doi: 10.1093/jn/113.10.2002. [DOI] [PubMed] [Google Scholar]
- Wei C. F., Chen S. H., Yang C. Y., Marcel Y. L., Milne R. W., Li W. H., Sparrow J. T., Gotto A. M., Jr, Chan L. Molecular cloning and expression of partial cDNAs and deduced amino acid sequence of a carboxyl-terminal fragment of human apolipoprotein B-100. Proc Natl Acad Sci U S A. 1985 Nov;82(21):7265–7269. doi: 10.1073/pnas.82.21.7265. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Young R. A., Davis R. W. Yeast RNA polymerase II genes: isolation with antibody probes. Science. 1983 Nov 18;222(4625):778–782. doi: 10.1126/science.6356359. [DOI] [PubMed] [Google Scholar]
- de Wet J. R., Fukushima H., Dewji N. N., Wilcox E., O'Brien J. S., Helinski D. R. Chromogenic immunodetection of human serum albumin and alpha-L-fucosidase clones in a human hepatoma cDNA expression library. DNA. 1984 Dec;3(6):437–447. doi: 10.1089/dna.1.1984.3.437. [DOI] [PubMed] [Google Scholar]