Dynamics and evolution of biological and social networks

Network control in gene expression profiles

Author: Marc Huett, Jacobs University Bremen.

Names and affiliation of other authors:

Oral presentation

The set of regulatory interactions between genes, mediated by transcription factors (TFs) forms a complex transcriptional regulatory network (TRN). For the bacterium E. coli we mapped microarray expression data onto the TRN to study the correspondence between a gene's expression level and its TRN characteristics at different levels of network organization.
In particular we look at the properties of effective networks derived from significant gene expression changes under variation of the two forms of control and find that upon limitations of one type of control (caused e.g. by mutation of a global DNA architectural factor) the other type can compensate for compromised regulation. Mutations of global regulators significantly enhance the digital control; in the presence of global DNA architectural proteins regulation is mostly of the analog type, coupling spatially neighboring genomic loci; together our data suggest that two logically distinct digital and analog types of control are balancing each other. By revealing two distinct logical types of control, our approach provides basic insights into both the organizational principles of transcriptional regulation and the mechanisms buffering genetic flexibility. We believe that the general concept of distinguishing logical types of control will apply to many complex biological networks.

Dynamics and evolution of biological and social networks. February 18-20th, 2008. Mallorca, Spain.