OBJECTIVES: Mice deficient in the transcription factor erythroid Krüppel-like factor, KLF1 (EKLF) die approximately 14.5 days postcoitum of anemia, attributed to decreased expression of the beta-globin gene. The objectives of this study were to rescue EKLF-deficient embryos with mice expressing gamma-globin from beta-spectrin or ankyrin promoters and to characterize expression of the major erythrocyte membrane genes in EKLF-deficient cells. METHODS: Transgenic beta-spectrin/gamma-globin or ankyrin/gamma-globin mice were bred onto EKLF-deficient and wild-type backgrounds. Animals were genotyped, gamma-globin mRNA levels measured, and hemoglobin electrophoresis performed. Steady-state mRNA levels and transcriptional rates of the major erythrocyte membrane protein genes were assayed. RESULTS: beta-spectrin/gamma-globin or ankyrin/gamma-globin mice on EKLF-deficient and wild-type backgrounds had identical levels of gamma-globin mRNA, indicating EKLF-independence of these promoters. gamma-Globin expression improved globin chain imbalance, but hemolysis was not improved and no live-born EKLF-deficient/(A)gamma-globin mice were obtained. Circulating erythroid cells from EKLF-deficient/(A)gamma-globin embryos exhibited hemolysis reminiscent of that seen in patients with severe erythrocyte membrane defects. Levels of beta-spectrin, ankyrin, and band 3 mRNA, but not alpha-spectrin, were decreased in EKLF-deficient fetal liver RNA. In a run-on assay, levels of transcription of the ankyrin and band 3 genes were decreased in EKLF-deficient fetal liver nuclei. CONCLUSIONS: These results indicate that the EKLF-responsive regions of the ankyrin and beta-spectrin genes are outside their promoters and that EKLF is necessary for full transcriptional activity of the ankyrin and band 3 genes; the results also provide additional evidence that defects in addition to beta-globin deficiency, including an abnormal erythrocyte membrane, contribute to the anemia and embryonic lethality in EKLF-deficient mice.
OBJECTIVES:Mice deficient in the transcription factor erythroid Krüppel-like factor, KLF1 (EKLF) die approximately 14.5 days postcoitum of anemia, attributed to decreased expression of the beta-globin gene. The objectives of this study were to rescue EKLF-deficient embryos with mice expressing gamma-globin from beta-spectrin or ankyrin promoters and to characterize expression of the major erythrocyte membrane genes in EKLF-deficient cells. METHODS: Transgenic beta-spectrin/gamma-globin or ankyrin/gamma-globin mice were bred onto EKLF-deficient and wild-type backgrounds. Animals were genotyped, gamma-globin mRNA levels measured, and hemoglobin electrophoresis performed. Steady-state mRNA levels and transcriptional rates of the major erythrocyte membrane protein genes were assayed. RESULTS: beta-spectrin/gamma-globin or ankyrin/gamma-globin mice on EKLF-deficient and wild-type backgrounds had identical levels of gamma-globin mRNA, indicating EKLF-independence of these promoters. gamma-Globin expression improved globin chain imbalance, but hemolysis was not improved and no live-born EKLF-deficient/(A)gamma-globinmice were obtained. Circulating erythroid cells from EKLF-deficient/(A)gamma-globin embryos exhibited hemolysis reminiscent of that seen in patients with severe erythrocyte membrane defects. Levels of beta-spectrin, ankyrin, and band 3 mRNA, but not alpha-spectrin, were decreased in EKLF-deficient fetal liver RNA. In a run-on assay, levels of transcription of the ankyrin and band 3 genes were decreased in EKLF-deficient fetal liver nuclei. CONCLUSIONS: These results indicate that the EKLF-responsive regions of the ankyrin and beta-spectrin genes are outside their promoters and that EKLF is necessary for full transcriptional activity of the ankyrin and band 3 genes; the results also provide additional evidence that defects in addition to beta-globin deficiency, including an abnormal erythrocyte membrane, contribute to the anemia and embryonic lethality in EKLF-deficientmice.
Authors: Michael R Tallack; Tom Whitington; Wai Shan Yuen; Elanor N Wainwright; Janelle R Keys; Brooke B Gardiner; Ehsan Nourbakhsh; Nicole Cloonan; Sean M Grimmond; Timothy L Bailey; Andrew C Perkins Journal: Genome Res Date: 2010-05-27 Impact factor: 9.043
Authors: Graham W Magor; Michael R Tallack; Kevin R Gillinder; Charles C Bell; Naomi McCallum; Bronwyn Williams; Andrew C Perkins Journal: Blood Date: 2015-02-27 Impact factor: 22.113
Authors: Patrick G Gallagher; Laurie A Steiner; Robert I Liem; Ashley N Owen; Amanda P Cline; Nancy E Seidel; Lisa J Garrett; David M Bodine Journal: J Clin Invest Date: 2010-11-22 Impact factor: 14.808
Authors: Stefan Schoenfelder; Tom Sexton; Lyubomira Chakalova; Nathan F Cope; Alice Horton; Simon Andrews; Sreenivasulu Kurukuti; Jennifer A Mitchell; David Umlauf; Daniela S Dimitrova; Christopher H Eskiw; Yanquan Luo; Chia-Lin Wei; Yijun Ruan; James J Bieker; Peter Fraser Journal: Nat Genet Date: 2009-12-13 Impact factor: 38.330
Authors: Andre M Pilon; Murat O Arcasoy; Holly K Dressman; Serena E Vayda; Yelena D Maksimova; Jose I Sangerman; Patrick G Gallagher; David M Bodine Journal: Mol Cell Biol Date: 2008-10-13 Impact factor: 4.272