Abstract: The present invention relates to rRNA-derived cDNA used as an internal standard or control to achieve normalization of hybridization signal detection in microarray biochip technology. Analysis of data obtained from a laser scanner during DNA microarray experiments first requires image processing. However, the data generated for the arrayed genes must be normalized before differentially expressed genes can be identified. Normalization is necessary to compensate for differences in labelling and detection efficiencies for the labels and for differences in the quantity of starting RNA from the samples examined in the assay. Because of its relatively invariant expression across tissues and treatments, 18S and 28S ribosomal RNAs are ideal internal controls for quantitative RNA analysis. A way to circumvent the technical difficulties of using ribosomal RNA as a control, because of its overabundance relative to that of other RNAs, is described and claimed in the present application.

Abstract: The invention provides a novel method for the screening and for the identification of nucleic acid binding factors (NABFs) or nucleic acid binding elements (NABEs) that are differentially active between two phenotypically different cell lines (normal and modified); in a particular cell type before and after a given treatment; or between two completely heterologous cell lines. The invention also provides methods for the simultaneous analysis of the effect of given compounds on multiple DNA-protein interactions. It further provides for the analysis of compounds that are nucleic acid binding factor analogs and compounds that selectively bind cis-acting nucleic acids.