RESUMO
BACKGROUND: Eukaryotic organisms are defined by the presence of a nucleus, which encloses the chromosomal DNA, and is characterized by its DNA content (C-value). Complex eukaryotic organisms contain organs and tissues that comprise interspersions of different cell types, within which polysomaty, endoreduplication, and cell cycle arrest is frequently observed. Little is known about the distribution of C-values across different cell types within these organs and tissues. RESULTS: We have developed, and describe here, a method to precisely define the C-value status within any specific cell type within complex organs and tissues of plants. We illustrate the application of this method to Arabidopsis thaliana, specifically focusing on the different cell types found within the root. CONCLUSION: The method accurately and conveniently charts C-value within specific cell types, and provides novel insight into developmental processes. The method is, in principle, applicable to any transformable organism, including mammals, within which cell type specificity of regulation of endoreduplication, of polysomaty, and of cell cycle arrest is suspected.
RESUMO
Flow cytometry and cell sorting provides unparalleled means for the identification and purification of specific cell types. It is a mature technology having been in existence commercially for the last 25 yr. High-throughput transcriptional profiling methods have emerged relatively recently. These provide the means to characterize efficiently the genome-wide contribution of individual genes to gene expression. A combination of these methods offers the opportunity to explore the relationship between gene expression and the ways in which different cell types are formed and maintained. This chapter provides a review of published methods for analysis of global gene expression within different cell types in complex tissues and organs, and provides practical details concerning microarray fabrication and use based on presynthesized 70-mer oligonucleotide array elements.
