Abstract
The gene coding for apolipoprotein AI (apoAI), a plasma protein involved in the transport of cholesterol and other lipids in the plasma, is expressed predominantly in liver and intestine. Previous work in our laboratory has shown that different cis-acting elements in the 5'-flanking region of the human apoAI gene control its expression in human hepatoma (HepG2) and colon carcinoma (Caco-2) cells. Hepatocyte-specific expression is mediated by elements within the -256 to -41 DNA region relative to the apoAI gene transcription start site (+1). In this study it was found that the -222 to -110 apoAI gene region is necessary and sufficient for expression in HepG2 cells. It was also found that this DNA region functions as a powerful hepatocyte-specific transcriptional enhancer. Gel retardation and DNase I protection experiments showed that HepG2 cells contain proteins that bind to specific sites, sites A (-214 to -192), B (-169 to -146), and C (-134 to -119), within this enhancer. Site-directed mutagenesis that prevents binding of these proteins to individual or different combinations of these sites followed by functional analysis of these mutants in HepG2 cells revealed that protein binding to any one of these sites in the absence of binding to the others was not sufficient for expression. Binding to any two of these sites in any combination was sufficient for only low levels of expression. Binding to all three sites was essential for maximal expression. These results indicate that the transcriptional activity of the apoAI gene in liver cells is dependent on synergistic interactions between transcription factors bound to its enhancer.
Full text
PDF










Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Apostolopoulos J. J., Howlett G. J., Fidge N. Effects of dietary cholesterol and hypothyroidism on rat apolipoprotein mRNA metabolism. J Lipid Res. 1987 Jun;28(6):642–648. [PubMed] [Google Scholar]
- Birkenmeier E. H., Gwynn B., Howard S., Jerry J., Gordon J. I., Landschulz W. H., McKnight S. L. Tissue-specific expression, developmental regulation, and genetic mapping of the gene encoding CCAAT/enhancer binding protein. Genes Dev. 1989 Aug;3(8):1146–1156. doi: 10.1101/gad.3.8.1146. [DOI] [PubMed] [Google Scholar]
- Brown M. S., Goldstein J. L. Lipoprotein metabolism in the macrophage: implications for cholesterol deposition in atherosclerosis. Annu Rev Biochem. 1983;52:223–261. doi: 10.1146/annurev.bi.52.070183.001255. [DOI] [PubMed] [Google Scholar]
- Carey M., Lin Y. S., Green M. R., Ptashne M. A mechanism for synergistic activation of a mammalian gene by GAL4 derivatives. Nature. 1990 May 24;345(6273):361–364. doi: 10.1038/345361a0. [DOI] [PubMed] [Google Scholar]
- Costa R. H., Grayson D. R., Darnell J. E., Jr Multiple hepatocyte-enriched nuclear factors function in the regulation of transthyretin and alpha 1-antitrypsin genes. Mol Cell Biol. 1989 Apr;9(4):1415–1425. doi: 10.1128/mcb.9.4.1415. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Courtois G., Morgan J. G., Campbell L. A., Fourel G., Crabtree G. R. Interaction of a liver-specific nuclear factor with the fibrinogen and alpha 1-antitrypsin promoters. Science. 1987 Oct 30;238(4827):688–692. doi: 10.1126/science.3499668. [DOI] [PubMed] [Google Scholar]
- Davidson N. O., Carlos R. C., Drewek M. J., Parmer T. G. Apolipoprotein gene expression in the rat is regulated in a tissue-specific manner by thyroid hormone. J Lipid Res. 1988 Nov;29(11):1511–1522. [PubMed] [Google Scholar]
- Dickson P. W., Howlett G. J., Schreiber G. Rat transthyretin (prealbumin). Molecular cloning, nucleotide sequence, and gene expression in liver and brain. J Biol Chem. 1985 Jul 5;260(13):8214–8219. [PubMed] [Google Scholar]
- Dignam J. D., Lebovitz R. M., Roeder R. G. Accurate transcription initiation by RNA polymerase II in a soluble extract from isolated mammalian nuclei. Nucleic Acids Res. 1983 Mar 11;11(5):1475–1489. doi: 10.1093/nar/11.5.1475. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dynan W. S. Modularity in promoters and enhancers. Cell. 1989 Jul 14;58(1):1–4. doi: 10.1016/0092-8674(89)90393-0. [DOI] [PubMed] [Google Scholar]
- Edlund T., Walker M. D., Barr P. J., Rutter W. J. Cell-specific expression of the rat insulin gene: evidence for role of two distinct 5' flanking elements. Science. 1985 Nov 22;230(4728):912–916. doi: 10.1126/science.3904002. [DOI] [PubMed] [Google Scholar]
- Elshourbagy N. A., Boguski M. S., Liao W. S., Jefferson L. S., Gordon J. I., Taylor J. M. Expression of rat apolipoprotein A-IV and A-I genes: mRNA induction during development and in response to glucocorticoids and insulin. Proc Natl Acad Sci U S A. 1985 Dec;82(23):8242–8246. doi: 10.1073/pnas.82.23.8242. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fried M., Crothers D. M. Equilibria and kinetics of lac repressor-operator interactions by polyacrylamide gel electrophoresis. Nucleic Acids Res. 1981 Dec 11;9(23):6505–6525. doi: 10.1093/nar/9.23.6505. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fromental C., Kanno M., Nomiyama H., Chambon P. Cooperativity and hierarchical levels of functional organization in the SV40 enhancer. Cell. 1988 Sep 23;54(7):943–953. doi: 10.1016/0092-8674(88)90109-2. [DOI] [PubMed] [Google Scholar]
- Goldstein J. L., Brown M. S. Regulation of the mevalonate pathway. Nature. 1990 Feb 1;343(6257):425–430. doi: 10.1038/343425a0. [DOI] [PubMed] [Google Scholar]
- Gorman C. M., Moffat L. F., Howard B. H. Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells. Mol Cell Biol. 1982 Sep;2(9):1044–1051. doi: 10.1128/mcb.2.9.1044. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gotto A. M., Jr, Pownall H. J., Havel R. J. Introduction to the plasma lipoproteins. Methods Enzymol. 1986;128:3–41. doi: 10.1016/0076-6879(86)28061-1. [DOI] [PubMed] [Google Scholar]
- Graham F. L., van der Eb A. J. A new technique for the assay of infectivity of human adenovirus 5 DNA. Virology. 1973 Apr;52(2):456–467. doi: 10.1016/0042-6822(73)90341-3. [DOI] [PubMed] [Google Scholar]
- Haddad I. A., Ordovas J. M., Fitzpatrick T., Karathanasis S. K. Linkage, evolution, and expression of the rat apolipoprotein A-I, C-III, and A-IV genes. J Biol Chem. 1986 Oct 5;261(28):13268–13277. [PubMed] [Google Scholar]
- Hardon E. M., Frain M., Paonessa G., Cortese R. Two distinct factors interact with the promoter regions of several liver-specific genes. EMBO J. 1988 Jun;7(6):1711–1719. doi: 10.1002/j.1460-2075.1988.tb03000.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Herbst R. S., Friedman N., Darnell J. E., Jr, Babiss L. E. Positive and negative regulatory elements in the mouse albumin enhancer. Proc Natl Acad Sci U S A. 1989 Mar;86(5):1553–1557. doi: 10.1073/pnas.86.5.1553. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Higuchi K., Law S. W., Hoeg J. M., Schumacher U. K., Meglin N., Brewer H. B., Jr Tissue-specific expression of apolipoprotein A-I (ApoA-I) is regulated by the 5'-flanking region of the human ApoA-I gene. J Biol Chem. 1988 Dec 5;263(34):18530–18536. [PubMed] [Google Scholar]
- Howell B. W., Lagacé M., Shore G. C. Activity of the carbamyl phosphate synthetase I promoter in liver nuclear extracts is dependent on a cis-acting C/EBP recognition element. Mol Cell Biol. 1989 Jul;9(7):2928–2933. doi: 10.1128/mcb.9.7.2928. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson P. F., McKnight S. L. Eukaryotic transcriptional regulatory proteins. Annu Rev Biochem. 1989;58:799–839. doi: 10.1146/annurev.bi.58.070189.004055. [DOI] [PubMed] [Google Scholar]
- Karlsson O., Edlund T., Moss J. B., Rutter W. J., Walker M. D. A mutational analysis of the insulin gene transcription control region: expression in beta cells is dependent on two related sequences within the enhancer. Proc Natl Acad Sci U S A. 1987 Dec;84(24):8819–8823. doi: 10.1073/pnas.84.24.8819. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Lai E., Prezioso V. R., Smith E., Litvin O., Costa R. H., Darnell J. E., Jr HNF-3A, a hepatocyte-enriched transcription factor of novel structure is regulated transcriptionally. Genes Dev. 1990 Aug;4(8):1427–1436. doi: 10.1101/gad.4.8.1427. [DOI] [PubMed] [Google Scholar]
- Laimins L. A., Khoury G., Gorman C., Howard B., Gruss P. Host-specific activation of transcription by tandem repeats from simian virus 40 and Moloney murine sarcoma virus. Proc Natl Acad Sci U S A. 1982 Nov;79(21):6453–6457. doi: 10.1073/pnas.79.21.6453. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leff T., Reue K., Melian A., Culver H., Breslow J. L. A regulatory element in the ApoCIII promoter that directs hepatic specific transcription binds to proteins in expressing and nonexpressing cell types. J Biol Chem. 1989 Sep 25;264(27):16132–16137. [PubMed] [Google Scholar]
- Maniatis T., Goodbourn S., Fischer J. A. Regulation of inducible and tissue-specific gene expression. Science. 1987 Jun 5;236(4806):1237–1245. doi: 10.1126/science.3296191. [DOI] [PubMed] [Google Scholar]
- Maxam A. M., Gilbert W. Sequencing end-labeled DNA with base-specific chemical cleavages. Methods Enzymol. 1980;65(1):499–560. doi: 10.1016/s0076-6879(80)65059-9. [DOI] [PubMed] [Google Scholar]
- Meehan R. R., Barlow D. P., Hill R. E., Hogan B. L., Hastie N. D. Pattern of serum protein gene expression in mouse visceral yolk sac and foetal liver. EMBO J. 1984 Aug;3(8):1881–1885. doi: 10.1002/j.1460-2075.1984.tb02062.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Metzger S., Leff T., Breslow J. L. Nuclear factors AF-1 and C/EBP bind to the human ApoB gene promoter and modulate its transcriptional activity in hepatic cells. J Biol Chem. 1990 Jun 15;265(17):9978–9983. [PubMed] [Google Scholar]
- Miller J. C., Barth R. K., Shaw P. H., Elliott R. W., Hastie N. D. Identification of a cDNA clone for mouse apoprotein A-1 (apo A-1) and its use in characterization of apo A-1 mRNA expression in liver and small intestine. Proc Natl Acad Sci U S A. 1983 Mar;80(6):1511–1515. doi: 10.1073/pnas.80.6.1511. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miller N. E. Associations of high-density lipoprotein subclasses and apolipoproteins with ischemic heart disease and coronary atherosclerosis. Am Heart J. 1987 Feb;113(2 Pt 2):589–597. doi: 10.1016/0002-8703(87)90638-7. [DOI] [PubMed] [Google Scholar]
- Mitchell P. J., Tjian R. Transcriptional regulation in mammalian cells by sequence-specific DNA binding proteins. Science. 1989 Jul 28;245(4916):371–378. doi: 10.1126/science.2667136. [DOI] [PubMed] [Google Scholar]
- Monaci P., Nicosia A., Cortese R. Two different liver-specific factors stimulate in vitro transcription from the human alpha 1-antitrypsin promoter. EMBO J. 1988 Jul;7(7):2075–2087. doi: 10.1002/j.1460-2075.1988.tb03047.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nicosia A., Monaci P., Tomei L., De Francesco R., Nuzzo M., Stunnenberg H., Cortese R. A myosin-like dimerization helix and an extra-large homeodomain are essential elements of the tripartite DNA binding structure of LFB1. Cell. 1990 Jun 29;61(7):1225–1236. doi: 10.1016/0092-8674(90)90687-a. [DOI] [PubMed] [Google Scholar]
- Ogami K., Hadzopoulou-Cladaras M., Cladaras C., Zannis V. I. Promoter elements and factors required for hepatic and intestinal transcription of the human ApoCIII gene. J Biol Chem. 1990 Jun 15;265(17):9808–9815. [PubMed] [Google Scholar]
- Ondek B., Gloss L., Herr W. The SV40 enhancer contains two distinct levels of organization. Nature. 1988 May 5;333(6168):40–45. doi: 10.1038/333040a0. [DOI] [PubMed] [Google Scholar]
- Panduro A., Shalaby F., Shafritz D. A. Changing patterns of transcriptional and post-transcriptional control of liver-specific gene expression during rat development. Genes Dev. 1987 Dec;1(10):1172–1182. doi: 10.1101/gad.1.10.1172. [DOI] [PubMed] [Google Scholar]
- Ptashne M. How eukaryotic transcriptional activators work. Nature. 1988 Oct 20;335(6192):683–689. doi: 10.1038/335683a0. [DOI] [PubMed] [Google Scholar]
- Pugh B. F., Tjian R. Mechanism of transcriptional activation by Sp1: evidence for coactivators. Cell. 1990 Jun 29;61(7):1187–1197. doi: 10.1016/0092-8674(90)90683-6. [DOI] [PubMed] [Google Scholar]
- Rajavashisth T. B., Dawson P. A., Williams D. L., Shackleford J. E., Lebherz H., Lusis A. J. Structure, evolution, and regulation of chicken apolipoprotein A-I. J Biol Chem. 1987 May 25;262(15):7058–7065. [PubMed] [Google Scholar]
- Sastry K. N., Seedorf U., Karathanasis S. K. Different cis-acting DNA elements control expression of the human apolipoprotein AI gene in different cell types. Mol Cell Biol. 1988 Feb;8(2):605–614. doi: 10.1128/mcb.8.2.605. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schaefer E. J. Clinical, biochemical, and genetic features in familial disorders of high density lipoprotein deficiency. Arteriosclerosis. 1984 Jul-Aug;4(4):303–322. doi: 10.1161/01.atv.4.4.303. [DOI] [PubMed] [Google Scholar]
- Sierra F., Tamone F., Mueller C. R., Schibler U. Differential in vitro transcription from the promoter of a rat alpha 2u globulin gene in liver and spleen nuclear extracts. Mol Biol Med. 1990 Apr;7(2):131–146. [PubMed] [Google Scholar]
- Sorci-Thomas M., Prack M. M., Dashti N., Johnson F., Rudel L. L., Williams D. L. Apolipoprotein (apo) A-I production and mRNA abundance explain plasma apoA-I and high density lipoprotein differences between two nonhuman primate species with high and low susceptibilities to diet-induced hypercholesterolemia. J Biol Chem. 1988 Apr 15;263(11):5183–5189. [PubMed] [Google Scholar]
- Sorci-Thomas M., Prack M. M., Dashti N., Johnson F., Rudel L. L., Williams D. L. Differential effects of dietary fat on the tissue-specific expression of the apolipoprotein A-I gene: relationship to plasma concentration of high density lipoproteins. J Lipid Res. 1989 Sep;30(9):1397–1403. [PubMed] [Google Scholar]
- Spiegelberg T., Bishop J. O. Tissue-specific gene expression in mouse hepatocytes cultured in growth-restricting medium. Mol Cell Biol. 1988 Aug;8(8):3338–3344. doi: 10.1128/mcb.8.8.3338. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Staels B., Auwerx J., Chan L., van Tol A., Rosseneu M., Verhoeven G. Influence of development, estrogens, and food intake on apolipoprotein A-I, A-II, and E mRNA in rat liver and intestine. J Lipid Res. 1989 Aug;30(8):1137–1145. [PubMed] [Google Scholar]
- Strobl W., Gorder N. L., Lin-Lee Y. C., Gotto A. M., Jr, Patsch W. Role of thyroid hormones in apolipoprotein A-I gene expression in rat liver. J Clin Invest. 1990 Mar;85(3):659–667. doi: 10.1172/JCI114489. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Strähle U., Schmid W., Schütz G. Synergistic action of the glucocorticoid receptor with transcription factors. EMBO J. 1988 Nov;7(11):3389–3395. doi: 10.1002/j.1460-2075.1988.tb03212.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Walsh A., Ito Y., Breslow J. L. High levels of human apolipoprotein A-I in transgenic mice result in increased plasma levels of small high density lipoprotein (HDL) particles comparable to human HDL3. J Biol Chem. 1989 Apr 15;264(11):6488–6494. [PubMed] [Google Scholar]