Background The actin cytoskeleton plays a crucial role in supporting and regulating numerous cellular processes. information recovered from the UniGene and RefSeq databases. Actichip performance was analysed by hybridisation with RNAs extracted from epithelial MCF-7 cells and human skeletal muscle. Using thoroughly standardised procedures, we obtained microarray images with excellent quality resulting in high data reproducibility. Actichip displayed a large dynamic range extending over three logs with a limit of sensitivity between one and ten copies of transcript per cell. The array allowed accurate detection of small changes in gene expression and reliable classification of samples based on the expression profiles of tissue-specific genes. When compared to two other oligonucleotide microarray platforms, Actichip showed similar sensitivity and concordant expression ratios. Moreover, Actichip was able to discriminate the highly similar actin isoforms whereas the two other platforms did not. Conclusion Our data demonstrate that Actichip is a powerful alternative to commercial high density microarrays for cytoskeleton gene profiling in normal or pathological samples. Actichip is available upon request. Background The actin CD123 cytoskeleton is an extremely powerful network of proteins polymers extending throughout the cytoplasm. It not only provides structural support for the cell, but also plays a central role in key cell processes including cellular morphogenesis, migration, division and cell communication. The actin cytoskeleton generates forces required for membrane extension and remodelling, motor protein-dependent cell contraction or membrane trafficking [1]. Recently, a nuclear function was identified for actin in the organisation of chromatin and gene expression [2,3]. In cells, the assembly and disassembly of actin filaments and their organisation into higher-order networks is regulated by actin-associated proteins which, in 152044-53-6 manufacture turn, are controlled by specific signalling pathways [1,4]. The formation of membrane-cytoskeleton specialisations not only depends on the spatio-temporal controlled recruitment of actin-binding proteins to cellular subdomains, but also around the repertoire of specific sets of 152044-53-6 manufacture cytoskeleton and regulatory proteins that cells express at a given state. In line, timely and spatially regulated expression of cytoskeletal genes is usually observed during embryonic development or terminal differentiation of cells in adults. The central role of the 152044-53-6 manufacture actin cytoskeleton in many essential cellular procedures makes the machine vunerable to mutations and modifications of gene appearance level that could cause an array of illnesses, including muscular dystrophies, amyloidosis, haematological disorders and malignancies [5,6]. Several illnesses occur from aberrant cell morphogenesis, motility or conversation due to deregulation of actin dynamics or company. For example, deregulated cell motility is usually a typical hallmark of tumour invasion and metastasis characterising cancer malignancy. Recent studies exhibited that tumour cell progression correlates with alterations of the expression profile of actin cytoskeleton genes and genes of upstream regulatory pathways [6-8]. Similarly, altered expression 152044-53-6 manufacture of genes encoding cytoskeletal proteins of the contractile system of muscle mass cells is observed in cardio-vascular disorders like heart failure [9]. Therefore, cytoskeleton proteins are potential markers for cell differentiation or disease, and might constitute promising novel targets for therapeutic treatments [10]. The basic set of structural and signalling protein components of the actin cytoskeleton is now identified and information on their biochemical or biological activities is available. However, gaps and controversies remain on how qualitative or quantitative changes in expression of these proteins are integrated to control actin dynamics and organisation in space and time. Elucidating the intricate interplay between the cytoskeletal components that cells use to build-up numerous cellular structures is usually hampered by the complexity of the actin cytoskeleton system. In this context, gene expression profiling using microarrays has the potential to yield a global overview on the set of actin cytoskeleton genes expressed by a cell at a given physiological or pathological state. The technique allows global and parallel investigations of cellular activity, and was used successfully to characterise the molecular basis of a variety of complex experimental models and diseases. Results obtained in previous profiling studies with high-density microarrays underline the potential of this strategy for detecting adjustments in the repertoire of appearance from the cytoskeleton genes [7,8]. Using an optimised experimental strategy, we created Actichip, a custom made oligonucleotide microarray made to research the appearance of actin cytoskeleton genes in a variety of cell systems. Actichip represents 327 individual genes, many of them encoding.