Magalhães Tiago R, Palmer Jessica, Tomancak Pavel, Pollard Katherine S
Programa Gulbenkian Doutoramento Biologia e Medicina, Centro Neurociências, Universidade de Coimbra, 3000-Coimbra, Portugal.
BMC Neurosci. 2007 Jul 31;8:59. doi: 10.1186/1471-2202-8-59.
During the development of the Drosophila central nervous system the process of midline crossing is orchestrated by a number of guidance receptors and ligands. Many key axon guidance molecules have been identified in both invertebrates and vertebrates, but the transcriptional regulation of growth cone guidance remains largely unknown. It is established that translational regulation plays a role in midline crossing, and there are indications that transcriptional regulation is also involved. To investigate this issue, we conducted a genome-wide study of transcription in Drosophila embryos using wild type and a number of well-characterized Drosophila guidance mutants and transgenics. We also analyzed a previously published microarray time course of Drosophila embryonic development with an axon guidance focus.
Using hopach, a novel clustering method which is well suited to microarray data analysis, we identified groups of genes with similar expression patterns across guidance mutants and transgenics. We then systematically characterized the resulting clusters with respect to their relevance to axon guidance using two complementary controlled vocabularies: the Gene Ontology (GO) and anatomical annotations of the Atlas of Pattern of Gene Expression (APoGE) in situ hybridization database. The analysis indicates that regulation of gene expression does play a role in the process of axon guidance in Drosophila. We also find a strong link between axon guidance and hemocyte migration, a result that agrees with mounting evidence that axon guidance molecules are co-opted in vertebrate vascularization. Cell cyclin activity in the context of axon guidance is also suggested from our array data. RNA and protein expression patterns of cell cyclins in axon guidance mutants and transgenics support this possible link.
This study provides important insights into the regulation of axon guidance in vivo.
在果蝇中枢神经系统发育过程中，中线交叉过程由多种导向受体和配体协调。许多关键的轴突导向分子已在无脊椎动物和脊椎动物中得到鉴定，但生长锥导向的转录调控在很大程度上仍不清楚。已经确定翻译调控在中线交叉中起作用，并且有迹象表明转录调控也参与其中。为了研究这个问题，我们使用野生型以及一些特征明确的果蝇导向突变体和转基因品系，对果蝇胚胎中的转录进行了全基因组研究。我们还分析了之前发表的以轴突导向为重点的果蝇胚胎发育微阵列时间进程。
使用hopach（一种非常适合微阵列数据分析的新型聚类方法），我们在导向突变体和转基因品系中鉴定出具有相似表达模式的基因群。然后，我们使用两个互补的受控词汇表：基因本体论（GO）和基因表达模式图谱（APoGE）原位杂交数据库的解剖学注释，系统地表征了所得聚类与轴突导向的相关性。分析表明基因表达调控在果蝇轴突导向过程中确实起作用。我们还发现轴突导向与血细胞迁移之间存在紧密联系，这一结果与越来越多的证据一致，即轴突导向分子在脊椎动物血管生成中被征用。我们的阵列数据还暗示了轴突导向背景下的细胞周期蛋白活性。轴突导向突变体和转基因品系中细胞周期蛋白的RNA和蛋白质表达模式支持了这种可能的联系。
本研究为体内轴突导向的调控提供了重要见解。
