Genome-wide analysis reveals NRP1 as a direct HIF1α-E2F7 target in the regulation of motorneuron guidance in vivo.
Genome-wide analysis reveals NRP1 as a direct HIF1α-E2F7 target in the regulation of motorneuron guidance in vivo.
复制标题
DOI：
10.1093/nar/gkv1471
复制
发表时间：
2016-05-05
影响因子：
14.9
通讯作者：
Bakker WJ
中科院分区：
文献类型：
--
作者：
de Bruin A;A Cornelissen PW;Kirchmaier BC;Mokry M;Iich E;Nirmala E;Liang KH;D Végh AM;Scholman KT;Groot Koerkamp MJ;Holstege FC;Cuppen E;Schulte-Merker S;Bakker WJ
在这项研究中，我们探索了由 E2F7 和 HIF1α 共同调节的转录网络的存在，因为我们表明 E2F7 的表达，如 HIF1α，在缺氧条件下被诱导，并且因为之前报道的 E2F7 与 HIF1α 相互作用的能力。我们的全基因组分析揭示了一个由 HIF1α 和 E2F7 直接控制的转录网络，并证明了 HIF1α -E2F7 复合物的刺激和抑制功能。在这个网络中，我们揭示了 Neuropilin 1 (NRP1) 作为 HIF1α-E2F7 抑制基因。通过进行体外和体内报告基因检测，我们证明 HIF1α-E2F7 介导的 NRP1 抑制依赖于 41 个碱基对的“E2F 结合位点枢纽”，为 HIF1α 在转录抑制中发挥先前未预料到的作用提供了分子机制。为了探索这种调节的生物学意义，我们进行了原位杂交，并观察到在对 e2f7/8 或 hif1α 进行吗啉抑制后，斑马鱼胚胎的脊髓运动神经元 (MN) 中 nrp1a 表达增强。与 nrp1a 的化学排斥作用一致，e2f7/8 或 hif1α 的吗啉抑制会导致 MN 截短，这在 TALEN 诱导的 nrp1ahu10012 突变体中得到挽救，并在 e2f7/8 突变体斑马鱼中进行表型复制。因此，我们得出结论，HIF1α-E2F7 复合物对 NRP1 的抑制可调节体内 MN 轴突的引导。
In this study, we explored the existence of a transcriptional network co-regulated by E2F7 and HIF1α, as we show that expression of E2F7, like HIF1α, is induced in hypoxia, and because of the previously reported ability of E2F7 to interact with HIF1α. Our genome-wide analysis uncovers a transcriptional network that is directly controlled by HIF1α and E2F7, and demonstrates both stimulatory and repressive functions of the HIF1α -E2F7 complex. Among this network we reveal Neuropilin 1 (NRP1) as a HIF1α-E2F7 repressed gene. By performing in vitro and in vivo reporter assays we demonstrate that the HIF1α-E2F7 mediated NRP1 repression depends on a 41 base pairs ‘E2F-binding site hub’, providing a molecular mechanism for a previously unanticipated role for HIF1α in transcriptional repression. To explore the biological significance of this regulation we performed in situ hybridizations and observed enhanced nrp1a expression in spinal motorneurons (MN) of zebrafish embryos, upon morpholino-inhibition of e2f7/8 or hif1α. Consistent with the chemo-repellent role of nrp1a, morpholino-inhibition of e2f7/8 or hif1α caused MN truncations, which was rescued in TALEN-induced nrp1ahu10012 mutants, and phenocopied in e2f7/8 mutant zebrafish. Therefore, we conclude that repression of NRP1 by the HIF1α-E2F7 complex regulates MN axon guidance in vivo.