Modifying transcript lengths of cycling mouse segmentation genes
Modifying transcript lengths of cycling mouse segmentation genes
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DOI：
10.1016/j.mod.2012.01.006
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发表时间：
2012-03-01
影响因子：
2.6
通讯作者：
Ish-Horowicz, David
中科院分区：
文献类型：
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作者：
Stauber, Michael;Laclef, Christine;Ish-Horowicz, David
体节、中轴骨骼和附着肌肉的前体的定期产生由分子振荡器（分割时钟）控制，该分子振荡器驱动未分割的体前中胚层（PSM）中靶基因的循环转录。生物钟是基于一个负反馈回路，它产生的转录脉冲与体节形成的周期相同。包括Notch途径基因Lunatic fringe（Lfng）和Notch靶标Hes7在内的几个振荡基因中的突变体导致有缺陷的体节发生和紊乱的中轴骨骼。这两个基因编码负调节Notch信号输出，但目前尚不清楚，如果他们只是次要的时钟目标，或者如果他们编码的主要，起搏器occurrence.In本文的组件，我们试图通过操纵延迟的反馈电路识别组件在主振荡器。我们构建了重组小鼠，其中Lfng和Hes7内含子被延长以延迟mRNA的产生。将第三个Hes7内含子延长10或20 kb会破坏准确的RNA剪接并使基因失活。在Lfng延长10 kb的小鼠中，Lfng表达和活性是正常的，但对分割没有明显影响。我们讨论了这些结果的相对贡献的转录和转录后延迟对定义的分割速度，和替代策略操纵的时钟周期。(C)2012爱思唯尔爱尔兰有限公司保留所有权利。
Regular production of somites, precursors of the axial skeleton and attached muscles is controlled by a molecular oscillator, the segmentation clock, which drives cyclic transcription of target genes in the unsegmented presomitic mesoderm (PSM). The clock is based on a negative feedback loop which generates pulses of transcription that oscillate with the same periodicity as somite formation. Mutants in several oscillating genes including the Notch pathway gene Lunatic fringe (Lfng) and the Notch target Hes7, result in defective somitogenesis and disorganised axial skeletons. Both genes encode negative regulators of Notch signalling output, but it is not yet clear if they are just secondary clock targets or if they encode components of a primary, pacemaker oscillator.In this paper, we try to identify components in the primary oscillator by manipulating delays in the feedback circuitry. We characterise recombinant mice in which Lfng and Hes7 introns are lengthened in order to delay mRNA production. Lengthening the third Hes7 intron by 10 or 20 kb disrupts accurate RNA splicing and inactivates the gene. Lfng expression and activity is normal in mice whose Lfng is lengthened by 10 kb, but no effects on segmentation are evident. We discuss these results in terms of the relative contributions of transcriptional and post-transcriptional delays towards defining the pace of segmentation, and of alternative strategies for manipulating the period of the clock. (C) 2012 Elsevier Ireland Ltd. All rights reserved.