Transcriptional and cell cycle control of erythropoiesis by E2F4

我们体内细胞数量的平衡是一个精心调控的过程，当受到干扰时，可能会导致许多威胁生命的疾病，如癌症。通过对小鼠的遗传学研究，我们之前发现E2F4是一种蛋白质，是体内正确数量的红细胞所必需的。缺乏E2F4会导致小鼠胚胎贫血。我们将这些小鼠作为一个模型进行研究，以了解体内的细胞生产是如何被控制的。在最近的研究中，我们发现增殖缺陷，特别是细胞分裂周期缺陷是导致胚胎中红细胞产生减少的主要原因。此外，我们还利用基因芯片技术，通过比较正常和E2F4缺陷小鼠的基因表达谱，来研究在没有E2F4的情况下哪些基因发生了变化。这些研究已经确定了大量基因，这些基因可能是E2F4的分子靶点，其表达缺陷可能最终导致这些小鼠的贫血。重要的是，我们的数据表明，E2F4在控制细胞分裂所需基因的开启方面具有全新的功能。在这个建议中，我们描述了一些方法来描述E2F4如何控制细胞分裂周期，以确定它可能控制的确切过程，例如DNA复制或将染色体分离成子细胞。我们还将测试我们的假设，即E2F4在启动有核红细胞中的基因方面扮演了一个新的角色。最后，我们描述了基因微阵列实验和一种新的启动子微阵列方法，以接近直接控制E2F4控制红细胞产生所需的分子。由于E2F家族或调节E2F家族的蛋白质的缺陷，即视网膜母细胞瘤，即pRb家族，已被认为是癌症发生的核心，这些研究将对这一途径在癌症中的治疗靶向具有广泛的意义。

The balance in the number of cells in our body is a carefully regulated process which, when disturbed, can lead to a number of life-threatening diseases such as cancer. Through genetic studies in the mouse, we previously identified E2F4 as a protein that is required for the correct number of red blood cells in the body. Lack of E2F4 results in anaemia in the mouse embryo. We have studied these mice as a model to understand how cell production in the body can be controlled. In recent studies, we have identified proliferation defects and in particular cell division cycle defects as the major cause for the decreased production of red blood cells in the embryo. In addition, we have utilised gene microarray technology to survey which genes change in the absence of E2F4 by comparing gene expression profiles in normal and E2F4 deficient mice. These studies have identified a large number of genes that could be molecular targets for E2F4 and whose defective expression could be ultimately responsible for the anaemia of these mice. Importantly, our data suggests a completely novel function for E2F4 in controlling the switching on of genes required for cell division. In this proposal, we describe approaches to characterise how E2F4 controls the cell division cycle to identify the exact process(es) it may control such as DNA replication or separation of chromosomes into daughter cells. We will also test our hypothesis for a novel role for E2F4 in being able to switch on genes in nucleated red blood cell. Finally, we describe gene microarray experiments and a new promoter microarray approach to close in on the molecules directly required for the E2F4 control of red blood cell production. Because defects in the E2F family of proteins or the proteins that regulate them, the retinoblastoma, pRB family, have been implicated as central for cancer development, these studies will have broad implications for therapeutic targeting of this pathway in cancer.