%0 Journal Article %T Transcriptional control in embryonic Drosophila midline guidance assessed through a whole genome approach %A Tiago R Magalh£żes %A Jessica Palmer %A Pavel Tomancak %A Katherine S Pollard %J BMC Neuroscience %D 2007 %I BioMed Central %R 10.1186/1471-2202-8-59 %X 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.The process by which axons cross the midline during development of the Central Nervous System (CNS) in Drosophila is of great interest and has been the focus of much scientific research [1,2]. After neuroblast delamination and cell fate decisions, axons undergo a journey that will eventually wire them to the appropriate targets. This journey includes a series of steps, one of which is the decision to cross (or not cross) the midline. Four key regulators of midline crossing are known: slit, robo, robo2 and comm. Growth cones in which the robo and robo2 receptors are present at the membrane sense the presence of the slit ligand and do not cross the midline [3,4]. Conversely, growth cones without robo and robo2 at the membrane are not able to respond to the repulsive cue of slit and do cross the midline. robo levels at the growth cone membrane are regulated by comm.A major question in midline cros %U http://www.biomedcentral.com/1471-2202/8/59