Abstract
Erythroid Krüppel-like factor (EKLF) is a red cell-restricted transcriptional activator that plays a dominant role in establishing high levels of beta-globin gene expression during erythroid ontogeny. Although its DNA binding domain belongs to the well-studied class of Krüppel-like zinc fingers, its proline-rich activation region has not been thoroughly examined. We have analyzed this region by monitoring the functional effects of its mutagenesis upon EKLF activity in vivo and in vitro. First, using co-transfection assays, we find that the transactivation region contains discrete stimulatory and inhibitory subdomains. Second, in vitro binding assays indicate that the inhibitory domain exerts its effect in cis by interfering with DNA binding. Third, in vivo competition assays demonstrate that EKLF interacts with a positive-acting cellular factor, and that the domain responsible for this trans interaction lies within a 40 amino acid sequence that is coincident with the EKLF minimal transactivation domain. Finally, site-directed mutagenesis of this domain implies that conformation and/or phosphorylation status of its central core may be critical for such interactions. These results point towards post-translational steric and/or allosteric control of EKLF function that may be important not just for its DNA binding ability, but also for its potential to interact with other proteins that fully establish the correct stereospecific array leading to efficient switching of beta-globin transcription during development.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bieker J. J. Isolation, genomic structure, and expression of human erythroid Krüppel-like factor (EKLF). DNA Cell Biol. 1996 May;15(5):347–352. doi: 10.1089/dna.1996.15.347. [DOI] [PubMed] [Google Scholar]
- Bieker J. J., Southwood C. M. The erythroid Krüppel-like factor transactivation domain is a critical component for cell-specific inducibility of a beta-globin promoter. Mol Cell Biol. 1995 Feb;15(2):852–860. doi: 10.1128/mcb.15.2.852. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Binétruy B., Smeal T., Karin M. Ha-Ras augments c-Jun activity and stimulates phosphorylation of its activation domain. Nature. 1991 May 9;351(6322):122–127. doi: 10.1038/351122a0. [DOI] [PubMed] [Google Scholar]
- Bungert J., Davé U., Lim K. C., Lieuw K. H., Shavit J. A., Liu Q., Engel J. D. Synergistic regulation of human beta-globin gene switching by locus control region elements HS3 and HS4. Genes Dev. 1995 Dec 15;9(24):3083–3096. doi: 10.1101/gad.9.24.3083. [DOI] [PubMed] [Google Scholar]
- Chiang C. M., Roeder R. G. Cloning of an intrinsic human TFIID subunit that interacts with multiple transcriptional activators. Science. 1995 Jan 27;267(5197):531–536. doi: 10.1126/science.7824954. [DOI] [PubMed] [Google Scholar]
- Chou P. Y., Fasman G. D. Empirical predictions of protein conformation. Annu Rev Biochem. 1978;47:251–276. doi: 10.1146/annurev.bi.47.070178.001343. [DOI] [PubMed] [Google Scholar]
- Colgan J., Wampler S., Manley J. L. Interaction between a transcriptional activator and transcription factor IIB in vivo. Nature. 1993 Apr 8;362(6420):549–553. doi: 10.1038/362549a0. [DOI] [PubMed] [Google Scholar]
- Donze D., Townes T. M., Bieker J. J. Role of erythroid Kruppel-like factor in human gamma- to beta-globin gene switching. J Biol Chem. 1995 Jan 27;270(4):1955–1959. doi: 10.1074/jbc.270.4.1955. [DOI] [PubMed] [Google Scholar]
- Engel J. D. Developmental regulation of human beta-globin gene transcription: a switch of loyalties? Trends Genet. 1993 Sep;9(9):304–309. doi: 10.1016/0168-9525(93)90248-g. [DOI] [PubMed] [Google Scholar]
- Felsenfeld G. Chromatin as an essential part of the transcriptional mechanism. Nature. 1992 Jan 16;355(6357):219–224. doi: 10.1038/355219a0. [DOI] [PubMed] [Google Scholar]
- Feng W. C., Southwood C. M., Bieker J. J. Analyses of beta-thalassemia mutant DNA interactions with erythroid Krüppel-like factor (EKLF), an erythroid cell-specific transcription factor. J Biol Chem. 1994 Jan 14;269(2):1493–1500. [PubMed] [Google Scholar]
- Frankel A. D., Berg J. M., Pabo C. O. Metal-dependent folding of a single zinc finger from transcription factor IIIA. Proc Natl Acad Sci U S A. 1987 Jul;84(14):4841–4845. doi: 10.1073/pnas.84.14.4841. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Garnier J., Osguthorpe D. J., Robson B. Analysis of the accuracy and implications of simple methods for predicting the secondary structure of globular proteins. J Mol Biol. 1978 Mar 25;120(1):97–120. doi: 10.1016/0022-2836(78)90297-8. [DOI] [PubMed] [Google Scholar]
- Gill G., Ptashne M. Negative effect of the transcriptional activator GAL4. Nature. 1988 Aug 25;334(6184):721–724. doi: 10.1038/334721a0. [DOI] [PubMed] [Google Scholar]
- Gonzalez G. A., Montminy M. R. Cyclic AMP stimulates somatostatin gene transcription by phosphorylation of CREB at serine 133. Cell. 1989 Nov 17;59(4):675–680. doi: 10.1016/0092-8674(89)90013-5. [DOI] [PubMed] [Google Scholar]
- Gregory R. C., Taxman D. J., Seshasayee D., Kensinger M. H., Bieker J. J., Wojchowski D. M. Functional interaction of GATA1 with erythroid Krüppel-like factor and Sp1 at defined erythroid promoters. Blood. 1996 Mar 1;87(5):1793–1801. [PubMed] [Google Scholar]
- Hainaut P., Milner J. Redox modulation of p53 conformation and sequence-specific DNA binding in vitro. Cancer Res. 1993 Oct 1;53(19):4469–4473. [PubMed] [Google Scholar]
- Higgs D. R., Wood W. G. Understanding erythroid differentiation. Curr Biol. 1993 Aug 1;3(8):548–550. doi: 10.1016/0960-9822(93)90054-r. [DOI] [PubMed] [Google Scholar]
- Hupp T. R., Lane D. P. Allosteric activation of latent p53 tetramers. Curr Biol. 1994 Oct 1;4(10):865–875. doi: 10.1016/s0960-9822(00)00195-0. [DOI] [PubMed] [Google Scholar]
- Hupp T. R., Meek D. W., Midgley C. A., Lane D. P. Regulation of the specific DNA binding function of p53. Cell. 1992 Nov 27;71(5):875–886. doi: 10.1016/0092-8674(92)90562-q. [DOI] [PubMed] [Google Scholar]
- Kim T. K., Roeder R. G. Proline-rich activator CTF1 targets the TFIIB assembly step during transcriptional activation. Proc Natl Acad Sci U S A. 1994 May 10;91(10):4170–4174. doi: 10.1073/pnas.91.10.4170. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kreider B. L., Orkin S. H., Ihle J. N. Loss of erythropoietin responsiveness in erythroid progenitors due to expression of the Evi-1 myeloid-transforming gene. Proc Natl Acad Sci U S A. 1993 Jul 15;90(14):6454–6458. doi: 10.1073/pnas.90.14.6454. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leuther K. K., Salmeron J. M., Johnston S. A. Genetic evidence that an activation domain of GAL4 does not require acidity and may form a beta sheet. Cell. 1993 Feb 26;72(4):575–585. doi: 10.1016/0092-8674(93)90076-3. [DOI] [PubMed] [Google Scholar]
- Lillie J. W., Green M. R. Transcription activation by the adenovirus E1a protein. Nature. 1989 Mar 2;338(6210):39–44. doi: 10.1038/338039a0. [DOI] [PubMed] [Google Scholar]
- Livingstone C., Patel G., Jones N. ATF-2 contains a phosphorylation-dependent transcriptional activation domain. EMBO J. 1995 Apr 18;14(8):1785–1797. doi: 10.1002/j.1460-2075.1995.tb07167.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lüscher B., Eisenman R. N. New light on Myc and Myb. Part II. Myb. Genes Dev. 1990 Dec;4(12B):2235–2241. doi: 10.1101/gad.4.12b.2235. [DOI] [PubMed] [Google Scholar]
- Marais R., Wynne J., Treisman R. The SRF accessory protein Elk-1 contains a growth factor-regulated transcriptional activation domain. Cell. 1993 Apr 23;73(2):381–393. doi: 10.1016/0092-8674(93)90237-k. [DOI] [PubMed] [Google Scholar]
- Merika M., Orkin S. H. Functional synergy and physical interactions of the erythroid transcription factor GATA-1 with the Krüppel family proteins Sp1 and EKLF. Mol Cell Biol. 1995 May;15(5):2437–2447. doi: 10.1128/mcb.15.5.2437. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meyer M. E., Gronemeyer H., Turcotte B., Bocquel M. T., Tasset D., Chambon P. Steroid hormone receptors compete for factors that mediate their enhancer function. Cell. 1989 May 5;57(3):433–442. doi: 10.1016/0092-8674(89)90918-5. [DOI] [PubMed] [Google Scholar]
- Migliaccio G., Migliaccio A. R., Kreider B. L., Rovera G., Adamson J. W. Selection of lineage-restricted cell lines immortalized at different stages of hematopoietic differentiation from the murine cell line 32D. J Cell Biol. 1989 Aug;109(2):833–841. doi: 10.1083/jcb.109.2.833. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miller I. J., Bieker J. J. A novel, erythroid cell-specific murine transcription factor that binds to the CACCC element and is related to the Krüppel family of nuclear proteins. Mol Cell Biol. 1993 May;13(5):2776–2786. doi: 10.1128/mcb.13.5.2776. [DOI] [PMC free article] [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]
- Nerlov C., Ziff E. B. Three levels of functional interaction determine the activity of CCAAT/enhancer binding protein-alpha on the serum albumin promoter. Genes Dev. 1994 Feb 1;8(3):350–362. doi: 10.1101/gad.8.3.350. [DOI] [PubMed] [Google Scholar]
- Nuez B., Michalovich D., Bygrave A., Ploemacher R., Grosveld F. Defective haematopoiesis in fetal liver resulting from inactivation of the EKLF gene. Nature. 1995 May 25;375(6529):316–318. doi: 10.1038/375316a0. [DOI] [PubMed] [Google Scholar]
- Orkin S. H. Globin gene regulation and switching: circa 1990. Cell. 1990 Nov 16;63(4):665–672. doi: 10.1016/0092-8674(90)90133-y. [DOI] [PubMed] [Google Scholar]
- Perkins A. C., Sharpe A. H., Orkin S. H. Lethal beta-thalassaemia in mice lacking the erythroid CACCC-transcription factor EKLF. Nature. 1995 May 25;375(6529):318–322. doi: 10.1038/375318a0. [DOI] [PubMed] [Google Scholar]
- Petersen J. M., Skalicky J. J., Donaldson L. W., McIntosh L. P., Alber T., Graves B. J. Modulation of transcription factor Ets-1 DNA binding: DNA-induced unfolding of an alpha helix. Science. 1995 Sep 29;269(5232):1866–1869. doi: 10.1126/science.7569926. [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]
- Pulverer B. J., Kyriakis J. M., Avruch J., Nikolakaki E., Woodgett J. R. Phosphorylation of c-jun mediated by MAP kinases. Nature. 1991 Oct 17;353(6345):670–674. doi: 10.1038/353670a0. [DOI] [PubMed] [Google Scholar]
- Russo M. W., Matheny C., Milbrandt J. Transcriptional activity of the zinc finger protein NGFI-A is influenced by its interaction with a cellular factor. Mol Cell Biol. 1993 Nov;13(11):6858–6865. doi: 10.1128/mcb.13.11.6858. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Southwood C. M., Downs K. M., Bieker J. J. Erythroid Krüppel-like factor exhibits an early and sequentially localized pattern of expression during mammalian erythroid ontogeny. Dev Dyn. 1996 Jul;206(3):248–259. doi: 10.1002/(SICI)1097-0177(199607)206:3<248::AID-AJA3>3.0.CO;2-I. [DOI] [PubMed] [Google Scholar]
- Struhl K. Mechanisms for diversity in gene expression patterns. Neuron. 1991 Aug;7(2):177–181. doi: 10.1016/0896-6273(91)90256-y. [DOI] [PubMed] [Google Scholar]
- Suzow J., Friedman A. D. The murine myeloperoxidase promoter contains several functional elements, one of which binds a cell type-restricted transcription factor, myeloid nuclear factor 1 (MyNF1). Mol Cell Biol. 1993 Apr;13(4):2141–2151. doi: 10.1128/mcb.13.4.2141. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tanese N., Pugh B. F., Tjian R. Coactivators for a proline-rich activator purified from the multisubunit human TFIID complex. Genes Dev. 1991 Dec;5(12A):2212–2224. doi: 10.1101/gad.5.12a.2212. [DOI] [PubMed] [Google Scholar]
- Tjian R., Maniatis T. Transcriptional activation: a complex puzzle with few easy pieces. Cell. 1994 Apr 8;77(1):5–8. doi: 10.1016/0092-8674(94)90227-5. [DOI] [PubMed] [Google Scholar]
- Townes T. M., Behringer R. R. Human globin locus activation region (LAR): role in temporal control. Trends Genet. 1990 Jul;6(7):219–223. doi: 10.1016/0168-9525(90)90182-6. [DOI] [PubMed] [Google Scholar]
- Wang Y., Prives C. Increased and altered DNA binding of human p53 by S and G2/M but not G1 cyclin-dependent kinases. Nature. 1995 Jul 6;376(6535):88–91. doi: 10.1038/376088a0. [DOI] [PubMed] [Google Scholar]
- Wijgerde M., Grosveld F., Fraser P. Transcription complex stability and chromatin dynamics in vivo. Nature. 1995 Sep 21;377(6546):209–213. doi: 10.1038/377209a0. [DOI] [PubMed] [Google Scholar]
- Williamson M. P. The structure and function of proline-rich regions in proteins. Biochem J. 1994 Jan 15;297(Pt 2):249–260. doi: 10.1042/bj2970249. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yu H., Chen J. K., Feng S., Dalgarno D. C., Brauer A. W., Schreiber S. L. Structural basis for the binding of proline-rich peptides to SH3 domains. Cell. 1994 Mar 11;76(5):933–945. doi: 10.1016/0092-8674(94)90367-0. [DOI] [PubMed] [Google Scholar]