Abstract
An important mechanism in the up-regulation of cytochrome P-450 2A5 (CYP2A5, coumarin hydroxylase, Coh) is the stabilization of the corresponding mRNA; some evidence suggests that proteins binding to CYP2A5 mRNA may be involved in this stabilization. Here we report that pyrazole, a well known inducer of CYP2A5 and stabilizer of its message, enhances the binding of a set of proteins to 32P-labelled 3'-untranslated region (3'UTR) of CYP2A5 to give 32P-labelled bands of apparent molecular mass 37/39, 45/48 and 70/72 kDa after UV cross-linking/RNase cleavage; in addition, we found different proteins binding to other parts of CYP2A5 mRNA. The 70/72 kDa bands are also formed with the 3'UTR of c-jun. The inducible proteins are found in different cellular subfractions at different concentrations, with a maximum of five-fold induction of binding activity in microsomes. When a gel-mobility-shift assay was combined with UV cross-linking to resolve different pyrazole-inducible RNA-protein complexes into single RNA-binding protein bands, the smallest complex contained a double band of 37/39 kDa, 45/48 kDa bands, 70/72 kDa bands, and additional weaker bands at higher molecular masses (around 120 kDa). This composition was found also for all other complexes detected by gel-mobility-shift assay; occasionally, bands at higher molecular masses were also observed. The proteins of the smallest complex might therefore represent a core with which other proteins interact to build up larger complexes. Binding of proteins 37/39 kDa and 70/72 kDa was located to a 20-base loop and adjacent sequences in a 70 nt AU-rich region of the 3'UTR of the CYP2A5. Based on our previous evidence, this 70-nt sequence may play an important role in the stabilization and processing of the message.
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- Aida K., Negishi M. Posttranscriptional regulation of coumarin 7-hydroxylase induction by xenobiotics in mouse liver: mRNA stabilization by pyrazole. Biochemistry. 1991 Aug 13;30(32):8041–8045. doi: 10.1021/bi00246a023. [DOI] [PubMed] [Google Scholar]
- Angel P., Karin M. The role of Jun, Fos and the AP-1 complex in cell-proliferation and transformation. Biochim Biophys Acta. 1991 Dec 10;1072(2-3):129–157. doi: 10.1016/0304-419x(91)90011-9. [DOI] [PubMed] [Google Scholar]
- Arnone M. I., Zannini M., Di Lauro R. The DNA binding activity and the dimerization ability of the thyroid transcription factor I are redox regulated. J Biol Chem. 1995 May 19;270(20):12048–12055. doi: 10.1074/jbc.270.20.12048. [DOI] [PubMed] [Google Scholar]
- Bohmann D., Bos T. J., Admon A., Nishimura T., Vogt P. K., Tjian R. Human proto-oncogene c-jun encodes a DNA binding protein with structural and functional properties of transcription factor AP-1. Science. 1987 Dec 4;238(4832):1386–1392. doi: 10.1126/science.2825349. [DOI] [PubMed] [Google Scholar]
- Camus A. M., Geneste O., Honkakoski P., Béréziat J. C., Henderson C. J., Wolf C. R., Bartsch H., Lang M. A. High variability of nitrosamine metabolism among individuals: role of cytochromes P450 2A6 and 2E1 in the dealkylation of N-nitrosodimethylamine and N-nitrosodiethylamine in mice and humans. Mol Carcinog. 1993;7(4):268–275. doi: 10.1002/mc.2940070410. [DOI] [PubMed] [Google Scholar]
- Crespi C. L., Penman B. W., Leakey J. A., Arlotto M. P., Stark A., Parkinson A., Turner T., Steimel D. T., Rudo K., Davies R. L. Human cytochrome P450IIA3: cDNA sequence, role of the enzyme in the metabolic activation of promutagens, comparison to nitrosamine activation by human cytochrome P450IIE1. Carcinogenesis. 1990 Aug;11(8):1293–1300. doi: 10.1093/carcin/11.8.1293. [DOI] [PubMed] [Google Scholar]
- Dallner G. Isolation of rough and smooth microsomes--general. Methods Enzymol. 1974;31:191–201. [PubMed] [Google Scholar]
- Emde B., Tegtmeier M., Hahnemann B., Legrum W. Inorganic tin -- a new selective inducer of the murine coumarin 7-hydroxylase (CYP2A5). Toxicology. 1996 Apr 15;108(1-2):73–78. doi: 10.1016/0300-483x(95)03285-n. [DOI] [PubMed] [Google Scholar]
- Geneste O., Raffalli F., Lang M. A. Identification and characterization of a 44 kDa protein that binds specifically to the 3'-untranslated region of CYP2a5 mRNA: inducibility, subcellular distribution and possible role in mRNA stabilization. Biochem J. 1996 Feb 1;313(Pt 3):1029–1037. doi: 10.1042/bj3131029. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gorospe M., Baglioni C. Degradation of unstable interleukin-1 alpha mRNA in a rabbit reticulocyte cell-free system. Localization of an instability determinant to a cluster of AUUUA motifs. J Biol Chem. 1994 Apr 22;269(16):11845–11851. [PubMed] [Google Scholar]
- Hahnemann B., Salonpä P., Pasanen M., Mäenpä J., Honkakoski P., Juvonen R., Lang M. A., Pelkonen O., Raunio H. Effect of pyrazole, cobalt and phenobarbital on mouse liver cytochrome P-450 2a-4/5 (Cyp2a-4/5) expression. Biochem J. 1992 Aug 15;286(Pt 1):289–294. doi: 10.1042/bj2860289. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hamilton B. J., Nagy E., Malter J. S., Arrick B. A., Rigby W. F. Association of heterogeneous nuclear ribonucleoprotein A1 and C proteins with reiterated AUUUA sequences. J Biol Chem. 1993 Apr 25;268(12):8881–8887. [PubMed] [Google Scholar]
- Kirby G. M., Batist G., Alpert L., Lamoureux E., Cameron R. G., Alaoui-Jamali M. A. Overexpression of cytochrome P-450 isoforms involved in aflatoxin B1 bioactivation in human liver with cirrhosis and hepatitis. Toxicol Pathol. 1996 Jul-Aug;24(4):458–467. doi: 10.1177/019262339602400408. [DOI] [PubMed] [Google Scholar]
- Kirby G. M., Chemin I., Montesano R., Chisari F. V., Lang M. A., Wild C. P. Induction of specific cytochrome P450s involved in aflatoxin B1 metabolism in hepatitis B virus transgenic mice. Mol Carcinog. 1994 Oct;11(2):74–80. doi: 10.1002/mc.2940110204. [DOI] [PubMed] [Google Scholar]
- Kirby G. M., Pelkonen P., Vatanasapt V., Camus A. M., Wild C. P., Lang M. A. Association of liver fluke (Opisthorchis viverrini) infestation with increased expression of cytochrome P450 and carcinogen metabolism in male hamster liver. Mol Carcinog. 1994 Oct;11(2):81–89. doi: 10.1002/mc.2940110205. [DOI] [PubMed] [Google Scholar]
- Leube R. E., Wiedenmann B., Franke W. W. Topogenesis and sorting of synaptophysin: synthesis of a synaptic vesicle protein from a gene transfected into nonneuroendocrine cells. Cell. 1989 Nov 3;59(3):433–446. doi: 10.1016/0092-8674(89)90028-7. [DOI] [PubMed] [Google Scholar]
- Lindberg R., Burkhart B., Ichikawa T., Negishi M. The structure and characterization of type I P-450(15) alpha gene as major steroid 15 alpha-hydroxylase and its comparison with type II P-450(15) alpha gene. J Biol Chem. 1989 Apr 15;264(11):6465–6471. [PubMed] [Google Scholar]
- Melton D. A., Krieg P. A., Rebagliati M. R., Maniatis T., Zinn K., Green M. R. Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter. Nucleic Acids Res. 1984 Sep 25;12(18):7035–7056. doi: 10.1093/nar/12.18.7035. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miles J. S., McLaren A. W., Forrester L. M., Glancey M. J., Lang M. A., Wolf C. R. Identification of the human liver cytochrome P-450 responsible for coumarin 7-hydroxylase activity. Biochem J. 1990 Apr 15;267(2):365–371. doi: 10.1042/bj2670365. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nagy E., Rigby W. F. Glyceraldehyde-3-phosphate dehydrogenase selectively binds AU-rich RNA in the NAD(+)-binding region (Rossmann fold). J Biol Chem. 1995 Feb 10;270(6):2755–2763. doi: 10.1074/jbc.270.6.2755. [DOI] [PubMed] [Google Scholar]
- Nakamaki T., Imamura J., Brewer G., Tsuruoka N., Koeffler H. P. Characterization of adenosine-uridine-rich RNA binding factors. J Cell Physiol. 1995 Dec;165(3):484–492. doi: 10.1002/jcp.1041650306. [DOI] [PubMed] [Google Scholar]
- Ostareck D. H., Ostareck-Lederer A., Wilm M., Thiele B. J., Mann M., Hentze M. W. mRNA silencing in erythroid differentiation: hnRNP K and hnRNP E1 regulate 15-lipoxygenase translation from the 3' end. Cell. 1997 May 16;89(4):597–606. doi: 10.1016/s0092-8674(00)80241-x. [DOI] [PubMed] [Google Scholar]
- Pelkonen P., Kirby G. M., Wild C. P., Bartsch H., Lang M. A. Metabolism of nitrosamines and aflatoxin B1 by hamster liver CYP2A enzymes. Chem Biol Interact. 1994 Oct;93(1):41–50. doi: 10.1016/0009-2797(94)90084-1. [DOI] [PubMed] [Google Scholar]
- Raunio H., Syngelmä T., Pasanen M., Juvonen R., Honkakoski P., Kairaluoma M. A., Sotaniemi E., Lang M. A., Pelkonen O. Immunochemical and catalytical studies on hepatic coumarin 7-hydroxylase in man, rat, and mouse. Biochem Pharmacol. 1988 Oct 15;37(20):3889–3895. doi: 10.1016/0006-2952(88)90070-6. [DOI] [PubMed] [Google Scholar]
- Ross J., Kobs G., Brewer G., Peltz S. W. Properties of the exonuclease activity that degrades H4 histone mRNA. J Biol Chem. 1987 Jul 5;262(19):9374–9381. [PubMed] [Google Scholar]
- Ross J. mRNA stability in mammalian cells. Microbiol Rev. 1995 Sep;59(3):423–450. doi: 10.1128/mr.59.3.423-450.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ryseck R. P., Hirai S. I., Yaniv M., Bravo R. Transcriptional activation of c-jun during the G0/G1 transition in mouse fibroblasts. Nature. 1988 Aug 11;334(6182):535–537. doi: 10.1038/334535a0. [DOI] [PubMed] [Google Scholar]
- Salonpä P., Pelkonen O., Kojo A., Pasanen M., Negishi M., Raunio H. Cytochrome P4502A5 expression and inducibility by phenobarbital is modulated by cAMP in mouse primary hepatocytes. Biochem Biophys Res Commun. 1994 Nov 30;205(1):631–637. doi: 10.1006/bbrc.1994.2712. [DOI] [PubMed] [Google Scholar]
- Satarug S., Lang M. A., Yongvanit P., Sithithaworn P., Mairiang E., Mairiang P., Pelkonen P., Bartsch H., Haswell-Elkins M. R. Induction of cytochrome P450 2A6 expression in humans by the carcinogenic parasite infection, opisthorchiasis viverrini. Cancer Epidemiol Biomarkers Prev. 1996 Oct;5(10):795–800. [PubMed] [Google Scholar]
- Squires E. J., Negishi M. Reciprocal regulation of sex-dependent expression of testosterone 15 alpha-hydroxylase (P-450(15 alpha)) in liver and kidney of male mice by androgen. Evidence for a single gene. J Biol Chem. 1988 Mar 25;263(9):4166–4171. [PubMed] [Google Scholar]
- Yamano S., Tatsuno J., Gonzalez F. J. The CYP2A3 gene product catalyzes coumarin 7-hydroxylation in human liver microsomes. Biochemistry. 1990 Feb 6;29(5):1322–1329. doi: 10.1021/bi00457a031. [DOI] [PubMed] [Google Scholar]
- Yamazaki H., Inui Y., Yun C. H., Guengerich F. P., Shimada T. Cytochrome P450 2E1 and 2A6 enzymes as major catalysts for metabolic activation of N-nitrosodialkylamines and tobacco-related nitrosamines in human liver microsomes. Carcinogenesis. 1992 Oct;13(10):1789–1794. doi: 10.1093/carcin/13.10.1789. [DOI] [PubMed] [Google Scholar]
- You Y., Chen C. Y., Shyu A. B. U-rich sequence-binding proteins (URBPs) interacting with a 20-nucleotide U-rich sequence in the 3' untranslated region of c-fos mRNA may be involved in the first step of c-fos mRNA degradation. Mol Cell Biol. 1992 Jul;12(7):2931–2940. doi: 10.1128/mcb.12.7.2931. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yun C. H., Shimada T., Guengerich F. P. Purification and characterization of human liver microsomal cytochrome P-450 2A6. Mol Pharmacol. 1991 Nov;40(5):679–685. [PubMed] [Google Scholar]
- Zhang W., Wagner B. J., Ehrenman K., Schaefer A. W., DeMaria C. T., Crater D., DeHaven K., Long L., Brewer G. Purification, characterization, and cDNA cloning of an AU-rich element RNA-binding protein, AUF1. Mol Cell Biol. 1993 Dec;13(12):7652–7665. doi: 10.1128/mcb.13.12.7652. [DOI] [PMC free article] [PubMed] [Google Scholar]