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梯度形成的蛋白质在果蝇胚胎确定性和随机模型：产妇的mRNA降解模型
Deterministic and stochastic models of bicoid protein gradient formation in Drosophila embryos: Modelling maternal mRNA degradationBicoid |
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| 课程网址: |
http://videolectures.net/licsb2010_liu_dsm/
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| 主讲教师: |
Wei Liu
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| 开课单位: |
南安普顿大学
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| 开课时间: |
2010-05-03
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| 课程语种: |
英语
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| 中文简介: |
图灵[1]提出了被称为形态发生素的一类分子的被动扩散作为一种有助于在胚胎发育过程中建立基因表达空间模式的机制。这种机制通常被建模为从母体沉积的信使RNA翻译的形态发生蛋白的被动扩散。这种扩散模型假设在稳定状态下建立所需的分布图时，源处的形态发生素不断供应[2]。使用在果蝇胚胎中建立前 - 后轴的双曲面形态发生素，我们注意到这种恒定来源的假设是不现实的，因为已知母体mRNA在产卵后的一定时间后会衰变。在[3]中，我们已经结合了一个更真实的形态源来源模型，因为母体mRNA应该预期会衰变。我们明确地将源作为恒定供应然后指数衰减，并用数值方法求解一维形态发生素的反应扩散方程传播。通过最小化模型输出和FlyEx数据库中发布的测量值之间的平方误差，我们展示了如何将扩散速率，mRNA和蛋白质衰变常数以及母体mRNA衰变的起始参数分配为合理的值。我们还扩展了这项工作，以进一步展示如何将这样一个现实的源模型与最近发布的流动模型[4]结合起来，考虑到平流运输。此外，基于随机模拟的模型[5]包括Bicoid分子反应也已在我们的工作中使用新的源模型实现。
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| 课程简介: |
Passive diffusion of a class of molecules known as morphogens as a mechanism that helps to establish spatial patterns of gene expression during embryonic development was proposed by Turing [1]. This mechanism is usually modelled as passive diffusion of morphogen proteins translated from maternally deposited messenger RNAs. Such diffusion models assume a constant supply of morphogens at the source throughout the establishment of the required profile at steady state [2]. Working with the bicoid morphogen which establishes the anterior-posterior axis in the Drosophila embryo, we note that this constant source assumption is unrealistic since the maternal mRNA is known to decay after a certain time since egg laying. In [3], we have incorporated a more realistic model of the morphogen source since the maternal mRNA should be expected to decay.We explicitly model the source as a constant supply followed by exponential decay and solve the reaction diffusion equation numerically for one dimensional morphogen propagation. By minimising the squared error between model outputs and measurements published in the FlyEx database, we show how parameters of diffusion rate, mRNA and protein decay constants, and the onset of maternal mRNA decay can be assigned sensible values. We also extend this work to further show how such a realistic source model may be combined with a recently published flow model [4] that takes into account advective transport. Moreover, a stochastic simulation based model [5] which includes Bicoid molecule reactions has also been implemented with new source model in our work.
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| 关 键 词: |
被动扩散; 基因表达; 信使RNA的被动扩散; 形态发生源模型
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| 课程来源: |
视频讲座网
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| 最后编审: |
2020-10-14：yumf
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| 阅读次数: |
76
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