模拟茎尖分生组织中 WUSCHEL 表达域的组织方式。

Modeling the organization of the WUSCHEL expression domain in the shoot apical meristem.

作者信息

Jönsson Henrik, Heisler Marcus, Reddy G Venugopala, Agrawal Vikas, Gor Victoria, Shapiro Bruce E, Mjolsness Eric, Meyerowitz Elliot M

机构信息

Department of Theoretical Physics, Complex Systems Division, Lund University Sweden.

出版信息

Bioinformatics. 2005 Jun;21 Suppl 1:i232-40. doi: 10.1093/bioinformatics/bti1036.

DOI:10.1093/bioinformatics/bti1036

PMID:15961462

Abstract

MOTIVATION

The above-ground tissues of higher plants are generated from a small region of cells situated at the plant apex called the shoot apical meristem. An important genetic control circuit modulating the size of the Arabidopsis thaliana meristem is a feed-back network between the CLAVATA3 and WUSCHEL genes. Although the expression patterns for these genes do not overlap, WUSCHEL activity is both necessary and sufficient (when expressed ectopically) for the induction of CLAVATA3 expression. However, upregulation of CLAVATA3 in conjunction with the receptor kinase CLAVATA1 results in the downregulation of WUSCHEL. Despite much work, experimental data for this network are incomplete and additional hypotheses are needed to explain the spatial locations and dynamics of these expression domains. Predictive mathematical models describing the system should provide a useful tool for investigating and discriminating among possible hypotheses, by determining which hypotheses best explain observed gene expression dynamics.

RESULTS

We are developing a method using in vivo live confocal microscopy to capture quantitative gene expression data and create templates for computational models. We present two models accounting for the organization of the WUSCHEL expression domain. Our preferred model uses a reaction-diffusion mechanism in which an activator induces WUSCHEL expression. This model is able to organize the WUSCHEL expression domain. In addition, the model predicts the dynamical reorganization seen in experiments where cells, including the WUSCHEL domain, are ablated, and it also predicts the spatial expansion of the WUSCHEL domain resulting from removal of the CLAVATA3 signal.

AVAILABILITY

An extended description of the model framework and image processing algorithms can be found at http://www.computableplant.org, together with additional results and simulation movies.

SUPPLEMENTARY INFORMATION

http://www.computableplant.org/ and alternatively for a direct link to the page, http://computableplant.ics.uci.edu/bti1036 can be accessed.

摘要

动机

高等植物的地上组织由位于植物顶端一个称为茎尖分生组织的小细胞区域产生。调节拟南芥分生组织大小的一个重要遗传控制回路是CLAVATA3和WUSCHEL基因之间的反馈网络。尽管这些基因的表达模式不重叠，但WUSCHEL活性对于CLAVATA3表达的诱导既是必需的也是充分的（当异位表达时）。然而，CLAVATA3与受体激酶CLAVATA1一起上调会导致WUSCHEL的下调。尽管进行了大量研究，但该网络的实验数据并不完整，需要额外的假设来解释这些表达域的空间位置和动态。描述该系统的预测性数学模型应该通过确定哪些假设最能解释观察到的基因表达动态，为研究和区分可能的假设提供有用的工具。

结果

我们正在开发一种方法，使用体内实时共聚焦显微镜来捕获定量基因表达数据并创建计算模型的模板。我们提出了两个解释WUSCHEL表达域组织的模型。我们首选的模型使用反应扩散机制，其中一种激活剂诱导WUSCHEL表达。该模型能够组织WUSCHEL表达域。此外，该模型预测了在包括WUSCHEL域在内的细胞被切除的实验中看到的动态重组，并且还预测了由于CLAVATA3信号去除导致的WUSCHEL域的空间扩展。