Université de Bourgogne, Facultés des Sciences, Unité Mixte de Recherche 5548 Associée au Centre National de la Recherche Scientifique, 6, Bd Gabriel, 21 000 Dijon, France.
BMC Genomics. 2010 Jan 19;11:47. doi: 10.1186/1471-2164-11-47.
The antenno-maxilary complex (AMC) forms the chemosensory system of the Drosophila larva and is involved in gustatory and olfactory perception. We have previously shown that a mutant allele of the homeodomain transcription factor Prospero (prosVoila1, V1), presents several developmental defects including abnormal growth and altered taste responses. In addition, many neural tracts connecting the AMC to the central nervous system (CNS) were affected. Our earlier reports on larval AMC did not argue in favour of a role of pros in cell fate decision, but strongly suggested that pros could be involved in the control of other aspect of neuronal development. In order to identify these functions, we used microarray analysis of larval AMC and CNS tissue isolated from the wild type, and three other previously characterised prospero alleles, including the V1 mutant, considered as a null allele for the AMC.
A total of 17 samples were first analysed with hierarchical clustering. To determine those genes affected by loss of pros function, we calculated a discriminating score reflecting the differential expression between V1 mutant and other pros alleles. We identified a total of 64 genes in the AMC. Additional manual annotation using all the computed information on the attributed role of these genes in the Drosophila larvae nervous system, enabled us to identify one functional category of potential Prospero target genes known to be involved in neurite outgrowth, synaptic transmission and more specifically in neuronal connectivity remodelling. The second category of genes found to be differentially expressed between the null mutant AMC and the other alleles concerned the development of the sensory organs and more particularly the larval olfactory system. Surprisingly, a third category emerged from our analyses and suggests an association of pros with the genes that regulate autophagy, growth and insulin pathways. Interestingly, EGFR and Notch pathways were represented in all of these three functional categories. We now propose that Pros could perform all of these different functions through the modulation of these two antagonistic and synergic pathways.
The current data contribute to the clarification of the prospero function in the larval AMC and show that pros regulates different function in larvae as compared to those controlled by this gene in embryos. In the future, the possible mechanism by which Pros could achieve its function in the AMC will be explored in detail.
触角-上颌复合体（AMC）构成了果蝇幼虫的化学感觉系统，参与味觉和嗅觉感知。我们之前已经表明，同源结构域转录因子 Prospero（prosVoila1，V1）的突变等位基因表现出多种发育缺陷，包括生长异常和味觉反应改变。此外，连接 AMC 与中枢神经系统（CNS）的许多神经束也受到影响。我们之前关于幼虫 AMC 的报告并没有证明 pros 在细胞命运决定中的作用，但强烈表明 pros 可能参与控制神经元发育的其他方面。为了确定这些功能，我们使用微阵列分析了从野生型和另外三个先前表征的 prospero 等位基因（包括被认为是 AMC 缺失突变的 V1 突变体）中分离的幼虫 AMC 和 CNS 组织。
首先使用层次聚类分析了总共 17 个样本。为了确定那些因 pros 功能丧失而受影响的基因，我们计算了一个区分分数，反映了 V1 突变体和其他 pros 等位基因之间的差异表达。我们在 AMC 中总共鉴定出 64 个基因。使用所有关于这些基因在果蝇幼虫神经系统中作用的计算信息进行的附加手动注释，使我们能够识别一个已知涉及神经突生长、突触传递的 Prospero 潜在靶基因的功能类别，更具体地说是神经元连接重塑。在 null 突变体 AMC 和其他等位基因之间差异表达的第二类基因涉及感觉器官的发育，特别是幼虫嗅觉系统。令人惊讶的是，我们的分析中出现了第三类，表明 pros 与调节自噬、生长和胰岛素途径的基因有关。有趣的是，EGFR 和 Notch 途径都存在于这三个功能类别中。我们现在提出，Pros 可以通过调节这两个拮抗和协同的途径来执行所有这些不同的功能。
当前的数据有助于阐明 pros 在幼虫 AMC 中的功能，并表明 pros 在幼虫中调节的功能与该基因在胚胎中控制的功能不同。未来，将详细探索 Pros 如何在 AMC 中实现其功能的可能机制。
