title: Dose-dependent regulation of primitive erythroid maturation and identity by the transcription factor Eklf.
abstract: The primitive erythroid (EryP) lineage is the first to differentiate during mammalian embryogenesis. Eklf/Klf1 is a transcriptional regulator that is essential for definitive erythropoiesis in the fetal liver. Dissection of the role(s) of Eklf within the EryP compartment has been confounded by the simultaneous presence of EryP and fetal liver-derived definitive erythroid (EryD) cells in the blood. To address this problem, we have distinguished EryP from their definitive counterparts by crossing Eklf(+/-) mutant and ε-globin::histone H2B-GFP transgenic mice. Eklf-deficient EryP exhibit membrane ruffling and a failure to acquire the typical discoidal erythroid shape but they can enucleate. Flow cytometric analyses of H2B-GFP(+) EryP revealed that Eklf heterozygosity results in the loss of Ter119 surface expression on EryP but not on EryD. Null mutation of Eklf resulted in abnormal expression of a range of surface proteins by EryP. In particular, several megakaryocyte markers were ectopically expressed by maturing Eklf-null EryP. Unexpectedly, the platelet tetraspanin CD9 was detected on nucleated wild-type EryP but not on mature EryD and thus provides a useful marker for purifying circulating EryP. We conclude that Eklf gene dosage is crucial for regulating the surface phenotype and molecular identity of maturing primitive erythroid cells.
authors: Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
authors: Joan
authors: J
authors: Isern
authors: Stuart T
authors: ST
authors: Fraser
authors: Zhiyong
authors: Z
authors: He
authors: Hailan
authors: H
authors: Zhang
authors: Margaret H
authors: MH
authors: Baron
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001483:Base Sequence; D001789:Blood Group Antigens / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D015672:Erythroid Precursor Cells / Q000166:cytology* / Q000378:metabolism*; D004920:Erythropoiesis / Q000235:genetics* / Q000502:physiology*; D005260:Female; D005333:Fetus / Q000166:cytology / Q000378:metabolism; D057895:Haploinsufficiency; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000378:metabolism; D008533:Megakaryocytes / Q000166:cytology / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009154:Mutation; D010641:Phenotype; D011247:Pregnancy; D060245:Tetraspanin 29
chemical_list: D015703:Antigens, CD; D001789:Blood Group Antigens; C554869:CD9 protein, human; C554870:Cd9 protein, mouse; D017931:DNA Primers; D051741:Kruppel-Like Transcription Factors; D008562:Membrane Glycoproteins; C489122:TER-119 antigen, mouse; D060245:Tetraspanin 29; C080774:erythroid Kruppel-like factor