EMZF-1--A NOVEL GENE REQUIRED FOR EMBRYONIC HEMATOPOIESIS

哺乳动物的造血系统由不同类型的细胞组成， 履行不同的和专门的职能。这些最终都是 分化的细胞是短暂的，由全能细胞池形成 推测起源于中胚层的造血干细胞 卵黄囊血岛的细胞。尽管在以下方面取得了进展 从成人骨髓中鉴定HSC活性，但没有这样的鉴定 同质的细胞群体已经被鉴定，没有遗传标记 存在识别这样的细胞的方法。我们假设唯一的文字记录是 最早的HSC将提供遗传谱系标记，使我们能够追踪 并操纵原始HSC的发育。 利用分子遗传学方法，我们最近鉴定了一种新的cdna。 从9.5天的血岛/卵黄囊cDNA文库中克隆人 髓系锌指(MZF)-1cDNA问题。这个新发现的cdna克隆， 胚胎外中胚层锌指-1(EM ZF-1)被证明表达 仅在卵黄囊的胚外中胚层，在胎儿 发育中胚胎的肝脏和心脏以及骨髓、脾和 成年小鼠的胸腺提示在哺乳动物的造血中起作用。这 该基因位于小鼠5号染色体上，含有12个C2H2类Kruppel 位于两个独立区域的锌指图案，这些区域与 MZF-1中的几个指状域。EMZF-1还包含一个 锌指基序下游的丙氨酸/精氨酸富集区。是这样的 在其他锌指基因中发现了一个结构域，似乎是 对转录调控很重要。EMZF-1基因定位于人类 7号染色体位于与髓系和淋巴细胞性白血病相关的区域。 有趣的是，PLZF，一个新发现的被确定为融合伙伴的基因 维甲酸受体-α突变为t(11；17)易位 与急性早幼粒细胞白血病有关，也与EMZF-1同源。 因此，EMZF-1是新形成的造血特异体的第三个成员 锌指基因家族，其功能似乎受 造血分化。EMZF-1的功能要求 反义基因产物出现在小鼠发育的早期 EMZF-1特异性寡核苷酸在14.5天内抑制造血 胎肝和成人骨髓体外培养。最后，另一个cDNA3 鉴定出与EMZF-1具有高交叉反应性的克隆。 该克隆Lm-1D已被部分测序，并被确定为 独立的c DNA。我们建议将特定于世系的 EMZF-1的表达及其基因组结构和启动子元件的鉴定 并开始分析其在体内的功能。EMZF-1的潜力 和高度相关的LM-1D克隆作为原始造血干细胞的分子标记 将在体外和体内探索它们在造血中的作用 白血病的发生也被阐明了。

The hematopoietic system in mammals is composed of diverse cell types that perform distinct and specialized functions. These terminally differentiated cells are short-lived, formed from a pool of totipotent hematopoietic stem cells (HSC) whose presumptive origin is the mesodermal cells of the yolk sac blood islands. Although progress has been made in the identification of HSC activity from the adult bone marrow, no such homogeneous cell population has been identified, and no genetic markers exist to identify such cells. We hypothesize that transcripts unique to the earliest HSC will provide genetic lineage markers enabling us to trace and manipulate the development of the primordial HSC. Using a molecular genetic approach we have recently identified a novel cDNA clone from a 9.5 day blood island/yolk sac cDNA library using the human myeloid zinc finger (MZF)-1 cDNAproble. This newly identified cDNA clone, extraembryonic mesoderm zinc finger-1 (EM ZF-1), was shown to be expressed exclusively in the extraembryonic mesoderm of the yolk sac, ina the fetal liver and heart of developing embryos and in the bone marrow, spleen and thymus of adult mice suggesting a role in mammalian hematopoiesis. This gene is located on mouse chromosome 5 and contains 12 C2H2 Kruppel-like zinc finger motifs in two separate regions which are highly homologous to several of the finger domains in MZF-1. EMZF-1 also contains an alanine/arginine-rich region downstream from the zinc finger motif. Such a domain has been found in other zinc finger genes and appears to be important for transcriptional regulation. The EMZF-1 gene maps to human chromosome 7 in an area associated with myeloid and lymphoid leukemias. Interestingly, PLZF, a newly discovered gene identified as a fusion partner with retinoid acid receptor-alpha in a variant t (11;17) translocation associated with acute promyelocytic leukemia, is also homologous to EMZF-1. Thus, EMZF-1 is the third member of a newly formed hematopoietic-specific zinc finger gene family whose function appears to be in the control of hematopoietic differentiation. The functional requirement for the EMZF-1 gene product appears early in mouse development since antisense oligonucleotides specific for EMZF-1 abrogates hematopoiesis in 14.5 day fetal liver and adult bone marrow cultures in vitro. Finally, another cDNA clone demonstrating high cross reactivity to the EMZF-1 was identified. This clone, LM-1D has been partially sequenced and determined to be an independent cDNA. We propose to characterize the lineage-specific expression of EMZF-1, identify its genomic structure and promoter elements and to begin the analysis of its function in vivo. The potential of EMZF-1 and the highly related LM-1D clone as molecular markers of primordial HSCs will be explored in vitro and in vivo and their function in hematopoiesis and leukemigenesis elucidated.