Kim Hyung-Gyoon, de Guzman Cristina G, Swindle C Scott, Cotta Claudiu V, Gartland Larry, Scott Edward W, Klug Christopher A
Department of Microbiology and Division of Developmental and Clinical Immunology, The University of Alabama at Birmingham, WTI Room 387, 1824 Sixth Ave South, Birmingham AL 35294-3300, USA.
Blood. 2004 Dec 15;104(13):3894-900. doi: 10.1182/blood-2002-08-2425. Epub 2004 Aug 24.
PU.1 is a member of the ETS family of transcription factors and is required for the development of multiple hematopoietic lineages. PU.1(-/-) mice die from hematopoietic failure at about embryonic day 18.5 (e18.5) and show a complete absence of B cells, mature T cells, and macrophages. This phenotype suggests that PU.1 may function at the level of the hematopoietic stem cell (HSC) or a multilineage progenitor. To investigate the role of PU.1 in the regulation of HSCs, PU.1(-/-) embryos were analyzed at various stages of embryonic development. The absolute number and frequency of HSCs were determined by flow cytometric analysis of c-Kit(+)Thy-1.1(lo)Lin(-)Sca-1(+) (KTLS) cells. We found that KTLS cells were absent or severely reduced in PU.1(-/-) fetal liver from e12.5 to e15.5. Progenitor cells with a c-Kit(+)Lin(-)AA4.1(+) and c-Kit(+)Lin(-)CD34(+) phenotype were also severely reduced. In addition, PU.1(-/-) fetal liver at e14.5 lacked common myeloid progenitors (CMPs) and granulocyte-macrophage progenitors (GMPs) but retained megakaryocyteerythroid progenitors (MEPs). Consistent with the loss of HSC activity, a 10-fold reduction in erythroid progenitors (mature erythroid burst-forming units [BFUEs]) was observed between e14.5 and e16.5. These data suggest that PU.1 plays an important role in the maintenance or expansion of HSC number in murine fetal liver.
PU.1是ETS转录因子家族的成员，是多种造血谱系发育所必需的。PU.1基因敲除（-/-）小鼠在胚胎第18.5天左右（e18.5）死于造血功能衰竭，表现为完全缺乏B细胞、成熟T细胞和巨噬细胞。这种表型表明PU.1可能在造血干细胞（HSC）或多谱系祖细胞水平发挥作用。为了研究PU.1在HSC调控中的作用，在胚胎发育的各个阶段对PU.1基因敲除（-/-）胚胎进行了分析。通过对c-Kit(+)Thy-1.1(lo)Lin(-)Sca-1(+)（KTLS）细胞进行流式细胞术分析来确定HSC的绝对数量和频率。我们发现，从e12.5到e15.5，PU.1基因敲除（-/-）胎肝中的KTLS细胞缺失或严重减少。具有c-Kit(+)Lin(-)AA4.1(+)和c-Kit(+)Lin(-)CD34(+)表型的祖细胞也严重减少。此外，e14.5时的PU.1基因敲除（-/-）胎肝缺乏常见髓系祖细胞（CMP）和粒细胞-巨噬细胞祖细胞（GMP），但保留了巨核细胞红系祖细胞（MEP）。与HSC活性丧失一致，在e14.5和e16.5之间观察到红系祖细胞（成熟红系爆式形成单位[BFUE]）减少了10倍。这些数据表明，PU.1在维持或扩大小鼠胎肝中HSC数量方面起着重要作用。
