Isolation of Polysomal RNA for Microarray Analysis

DNA microarrays have been used extensively in recent years to study mRNA expression profiles of different cell types under various growth conditions. These steady-state mRNA profiles provide a wealth of information about cellular functions and responses. However, they do not necessarily reflect the ultimate gene expression profile of a cell since the step of translation might lead to discrepancies between the mRNA profile and the profile of the actual functioning unit in the cell, the protein (e.g., 1 ,2 ).