Chromosomal patterns of gene expression from microarray data: methodology, validation and clinical relevance in gliomas

Background  

Expression microarrays represent a powerful technique for the simultaneous investigation of thousands of genes. The evidence that genes are not randomly distributed in the genome and that their coordinated expression depends on their position on chromosomes has highlighted the need for mathematical approaches to exploit this dependency for the analysis of expression data-sets.     

Cytochemical identification of HSP110 during early mouse facial development.

Apoptotic cell death constitutes a common phenomenon observed during development. This process plays an important role in the regulation of cell populations and in early differentiation of embryonic organs. Several teratologic situations are considered as resulting in a dramatic increase of the apoptotic process. In mammalian cells, heat shock proteins (HSPs), expressed or increased in response to various stresses, act as molecular chaperones in physiological conditions. In order to determine specific histochemical markers of apoptotic cells in normal craniofacial development, we observed the expression of stress proteins (HSPs) 70, 86, and 110. The apoptotic pattern of mesectodermal cell death areas was confirmed using both nuclear staining (Feulgen) and specific labeling of DNA fragmentation (TUNEL). These areas are localized in the proximal parts of the first and second visceral arches. They are located in mesectodermal and ganglionic cells. Apoptotic mesectodermal populations strongly express HSP110, as shown by the cytochemical identification of HSP110 and by double staining HSP110-TUNEL, suggesting that this protein could be considered as a new marker for apoptotic embryonic cells, and could be used in further teratologic studies to better quantify induced cell death.