Drissen Roy, von Lindern Marieke, Kolbus Andrea, Driegen Siska, Steinlein Peter, Beug Hartmut, Grosveld Frank, Philipsen Sjaak
Erasmus MC, Department of Cell Biology, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.
Mol Cell Biol. 2005 Jun;25(12):5205-14. doi: 10.1128/MCB.25.12.5205-5214.2005.
Development of red blood cells requires the correct regulation of cellular processes including changes in cell morphology, globin expression and heme synthesis. Transcription factors such as erythroid Kruppel-like factor EKLF (Klf1) play a critical role in erythropoiesis. Mice lacking EKLF die around embryonic day 14 because of defective definitive erythropoiesis, partly caused by a deficit in beta-globin expression. To identify additional target genes, we analyzed the phenotype and gene expression profiles of wild-type and EKLF null primary erythroid progenitors that were differentiated synchronously in vitro. We show that EKLF is dispensable for expansion of erythroid progenitors, but required for the last steps of erythroid differentiation. We identify EKLF-dependent genes involved in hemoglobin metabolism and membrane stability. Strikingly, expression of these genes is also EKLF-dependent in primitive, yolk sac-derived, blood cells. Consistent with lack of upregulation of these genes we find previously undetected morphological abnormalities in EKLF-null primitive cells. Our data provide an explanation for the hitherto unexplained severity of the EKLF null phenotype in erythropoiesis.
红细胞的发育需要对细胞过程进行正确调控，包括细胞形态变化、珠蛋白表达和血红素合成。转录因子如红系Kruppel样因子EKLF（Klf1）在红细胞生成中起关键作用。缺乏EKLF的小鼠在胚胎第14天左右死亡，原因是确定性红细胞生成存在缺陷，部分原因是β-珠蛋白表达不足。为了鉴定其他靶基因，我们分析了在体外同步分化的野生型和EKLF基因敲除的原代红系祖细胞的表型和基因表达谱。我们发现，EKLF对于红系祖细胞的扩增并非必需，但对于红系分化的最后步骤是必需的。我们鉴定出了参与血红蛋白代谢和膜稳定性的EKLF依赖性基因。令人惊讶的是，这些基因在原始的、卵黄囊来源的血细胞中的表达也是EKLF依赖性的。与这些基因缺乏上调一致，我们在EKLF基因敲除的原始细胞中发现了以前未检测到的形态异常。我们的数据为迄今为止在红细胞生成中无法解释的EKLF基因敲除表型的严重性提供了解释。
