HOX genes regulate Rac1 activity in hematopoietic cells through control of Vav2 expression
HOX genes regulate Rac1 activity in hematopoietic cells through control of Vav2 expression
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HOX基因通过控制Vav2表达来调节造血细胞中的Rac1活性
DOI：
10.1038/leu.2012.166
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发表时间：
2012
期刊：
影响因子：
11.4
通讯作者：
Slany R.K.
中科院分区：
文献类型：
--
作者：
Breitinger C;Maethner E;Garcia-Cuellar M.P;Schambony A;Fischer K.D;Schilling K;Slany R.K.
HOX 同源盒转录因子不仅是片段同一性的主要调节因子，而且对于正确的血液形成也有帮助（Argiropoulos 和 Humphries1 和 Eklund2 进行了综述）。造血干细胞和祖细胞 (HSPC) 的生理学受 HOX 蛋白的直接控制。特别是，“HOX-A”和“HOX-B”旁系同源组的成员主要在 HSPC 中表达。分化需要 HOX 基因的下调，成熟的血细胞通常不再表达 HOX 蛋白。在恶性造血过程中经常观察到异常的 HOX 活性以及随之而来的分化障碍，因此使 HOX 成员成为真正的癌基因。尽管它们在造血过程中很重要，但对于 HSPC 生物学和白血病发生至关重要的 HOX 附属途径却知之甚少。已经发表了一些研究试图鉴定造血细胞中的 HOX 靶基因。 3-5 一个经常出现的问题是 HOX“主调控因子”控制下的大量基因。很难区分对造血具有重要意义的“驱动”基因和“旁观者”基因，后者可能是真正的 HOX 目标，但对 HSPC 发育影响较小。在这项研究中，我们试图通过识别 HOXA1 和 Hoxa9（两种不相关但都转化 HOX 蛋白）之间共享的共同基因表达模式来解决这个问题。 6 如前所述，6 唇型 HOXA1 以及腹部型 HOXA9 将初级造血祖细胞转化为永生化成髓细胞。因此，我们推断，骨髓转化所必需的基因应该由两种 HOX 蛋白以类似的方式触发，因此这些基因应该在共同靶标中富集。为了研究这一假设，我们使用了 HOXA1 和 Hoxa9 的他莫昔芬 (TAM) 诱导衍生物，这些衍生物是通过融合修饰的雌激素配体结合域 (ER) 而产生的，如先前报道的。 6（Hoxa9 与人 HOXA9 具有 97% 同源性；因此我们决定使用现有的小鼠克隆。）正如预期的那样，用两种 HOX 衍生物转导7祖细胞会导致细胞因子依赖性成髓细胞群体的永生化，这些细胞可以在补充有 100 ng/ml SCF、IL-3、IL-6、GM-CSF 和 100 各 10 ng/ml 的培养基中培养。 nM 4-羟基-TAM。重要的是，这些细胞在没有 TAM 的情况下不会凋亡，而是启动正常的分化程序，并在大约 1 周内以成熟粒细胞和巨噬细胞的出现而终止（数据未显示）。为来自不同供体动物的每个 HOX 构建体创建了四个单独的细胞系。在 TAM 存在的情况下以及 TAM 撤除后 72 小时分离 RNA。选择这个时间表是因为在那个时间点可以检测到几个分化基因表达的第一个显着变化。表达谱比较（以登录号 E-MEXP-3648 保存在 ArrayExpress 的原始数据）显示，HOXA1 和 Hoxa9 分别显着（变化 > 1.7 倍，Po0.1）上调了 948 个和 374 个基因。可以检测到类似数量但行为相反的转录本（HOXA1 和 Hoxa9 细胞中 HOX 失活后，731 和 441 个基因表达增加）。在所有 HOX 响应转录本中，HOXA1 和 Hoxa9 共有 61 个上调基因和 57 个下调基因的核心组。这包括成髓细胞瘤癌基因 c-Myb
HOX homeobox transcription factors are not only master regulators of segment identity but also instrumental for proper blood formation (reviewed in Argiropoulos and Humphries1 and Eklund2). The physiology of hematopoietic stem and progenitor cells (HSPC) is under the direct control of HOX proteins. In particular, members of the ‘HOX-A’and ‘HOX-B’paralog groups are predominantly expressed in HSPC. Differentiation requires a downregulation of HOX genes and mature blood cells usually do not express HOX proteins any more. An abnormal HOX activity and, concomitantly, a block of differentiation are frequently observed in malignant hematopoiesis, thus qualifying HOX members as bona fide oncogenes. Despite their importance in hematopoiesis, little is known about the HOX-subordinate pathways that are crucial for HSPC biology and leukemogenesis. A few studies have been published trying to identify HOX target genes in hematopoietic cells. 3–5 One recurrent problem is the multitude of genes that are under control of the HOX ‘master regulators’. It is difficult to discriminate the ‘driver’genes with importance in hematopoiesis from ‘bystanders’ that may be true HOX targets but have less impact on HSPC development. In this study we tried to address this problem by identifying a common gene expression pattern shared between HOXA1 and Hoxa9, two unrelated, yet both transforming HOX proteins. 6As shown previously, 6 the labial-type HOXA1, as well as the abdominal-like HOXA9, transforms primary hematopoietic progenitors into immortalized myeloblasts. Therefore we reasoned that genes essential for myeloid transformation should be triggered by both HOX proteins in a similar fashion and hence these genes should be enriched within the common targets. To investigate this hypothesis we used tamoxifen (TAM)-inducible derivatives of HOXA1 and Hoxa9 created by fusion of a modified estrogen–ligand binding domain (ER) as reported previously. 6 (Hoxa9 shares 97% homology with human HOXA9; therefore we decided to use an existent murine clone.) As expected, transduction7 of progenitor cells with both HOX derivatives leads to the immortalization of cytokine-dependent, myeloblastic populations that could be cultivated in medium supplemented with 100 ng/ml SCF, 10 ng/ml each of IL-3, IL-6, GM-CSF, and 100 nM 4-hydroxy-TAM. Importantly, these cells did not apoptose in the absence of TAM, but initiated a normal program of differentiation, terminating with the appearance of mature granulocytes and macrophages within approximately 1 week (data not shown). Four individual cell lines were created for each HOX construct from different donor animals. RNA was isolated with TAM present and 72h after TAM withdrawal. This schedule was chosen because first significant changes in expression of several differentiation genes became detectable at that time point. Comparison of the expression profiles (raw data deposited at ArrayExpress under accession number E-MEXP-3648) revealed 948 and 374 genes that were significantly (change> 1.7-fold, Po0. 1) upregulated by HOXA1 and Hoxa9, respectively. A similar number of transcripts with opposite behavior could be detected (731 and 441 genes increased expression after HOX inactivation in HOXA1 and Hoxa9 cells). Among all HOX-responsive transcripts, a core group of 61 upregulated and 57 downregulated genes was shared by HOXA1 and Hoxa9. This included the myeloblastosis oncogene c-Myb that had been
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影响因子：
20.3
作者：
Mizukawa, Benjamin;Wei, Junping;Mulloy, James C.
通讯作者：
Mulloy, James C.
HOX蛋白在白血病发生中的作用：对造血中关键调节事件的见解。
影响因子：
--
作者：
Eklund E
通讯作者：
Eklund E
影响因子：
20.3
作者：
Huang, Yongsheng;Sitwala, Kajal;Hess, Jay L.
通讯作者：
Hess, Jay L.
影响因子：
50.3
作者：
Wei, Junping;Wunderlich, Mark;Mulloy, James C.
通讯作者：
Mulloy, James C.
影响因子：
20.3
作者：
Hess, Jay L.;Bittner, Claudia B.;Slany, Robert K.
通讯作者：
Slany, Robert K.