  Identity, response to external stimuli, and spatial architecture of a living
system are central topics of molecular biology. Presently, they are largely
seen as a result of the interplay between a gene repertoire and the regulatory
machinery of the cell. At the transcriptional level, the cis-regulatory regions
establish sets of interdependencies between transcription factors and genes,
including other transcription factors. These ``transcription networks'' are too
large to be approached globally with a detailed dynamical model. In this paper,
we describe an approach to this problem that focuses solely on the
compatibility between gene expression patterns and signal integration
functions, discussing calculations carried on the simplest, Boolean,
realization of the model, and a first application to experimental data sets.
