Regulation of gene expression by bHLHPAS protein transcriptional complexes

我是一名分子生物学家，希望通过细胞多蛋白机器确定基因调控的分子机制。我们鉴定了一个转录复合体，包括缺氧诱导因子1 （HIF）、芳烃受体核转运子（ARNT）、甲状腺激素受体/视网膜母细胞瘤蛋白相互作用蛋白-230 （TRIP230）和视网膜母细胞瘤蛋白（Rb），这些转录复合体参与了负责发育、细胞转化适应低氧和组织损伤的特定基因组的调控。我们在人类细胞系中消融了Rb，发现调节组织发育、细胞运动和适应性反应的遗传程序以缺氧依赖的方式对Rb的损失很敏感。这些基因中有很大一部分聚集在染色体上，表明该复合体调节染色质组织，从而影响特定的遗传程序。

I am a molecular biologist with a desire to determine the molecular mechanisms of gene regulation by cellular multi-protein machines. We have characterized a transcriptional complex consisting of hypoxia-inducible factor1 (HIF), the aryl hydrocarbon receptor nuclear translocator (ARNT), the thyroid hormone receptor/retinoblastoma protein interacting protein-230 (TRIP230), and the retinoblastoma protein (Rb) involved in the regulation of specific sets of genes responsible for development, cellular transformation adaptation to low oxygen, and tissue damage. We have ablated Rb in human cell lines and found that genetic programs regulating tissue development, cellular motility and adaptive responses are sensitive to loss of Rb in a hypoxia-dependent fashion. A significant proportion of these genes are clustered on chromosomes suggesting that this complex regulates chromatin organization, thereby affecting specific genetic programs. I propose to expand our previous findings by focusing on how the hypoxia-inducible multi-protein complex regulates gene transcription and affects the outcomes of adaptive cellular responses and malignant transformation. Specifically, my short-term goal is to elucidate the means by which the hypoxia-inducible factor-/ (HIF1-ARNT) co-regulatory complex directs the expression of specific genetic programs and regulate chromatin organization. The specific aims of this proposal are; (1) To identify and characterize proteins mediating the HIF-ARNT_TRIP-Rb (HATR) complex activity. Factors recruited by Rb to attenuate the hypoxic response represent novel targets to manipulate genetic programs that regulate cell differentiation and adaptation to environmental stress. (2). To analyze long-term hypoxia-dependent gene silencing and de-repression after loss of Rb. Elucidation of the molecular mechanisms underlying Rb regulated HIF adaptive responses will enable us to identify malleable targets to remediate Rb loss. (3) To define the cistrome (DNA binding sites) of the HATR complex. This strategy will identify down-stream effectors of the biological responses regulated by the HATR complex and the manner in which it controls chromatin organization. These aims are novel in that they define a new role for a transcriptional complex known to be involved in the biology of cell development, adaptive responses to environmental stimuli and many pathological conditions. Following this strategy, we will in five years, have; (i) a realistic understanding of how the HATR complex directs specific genetic programs to regulate adaptive responses, and: (ii) identified protein targets regulating the HATR complex, its function and responses. These targets may be manipulated in the future to develop a more rational and targeted therapeutic approach to a number of pathologies including those involving cellular transformation.