Predicting gene-regulation functions: lessons from temperate bacteriophages.
Gene-regulation functions (GRF) provide a unique characteristic of a cis-regulatory module (CRM), relating the concentrations of transcription factors (input) to the promoter activities (output). The challenge is to predict GRFs from the sequence. Here we systematically consider the lysogeny-lysis CRMs of different temperate bacteriophages such as the Lactobacillus casei phage A2, Escherichia coli phages lambda, and 186 and Lactococcal phage TP901-1. This study allowed explaining a recent experimental puzzle on the role of Cro protein in the lambda switch. Several general conclusions have been drawn: 1), long-range interactions, multilayer assembly and DNA looping may lead to complex GRFs that cannot be described by linear functions of binding site occupancies; 2), in general, GRFs cannot be described by the Boolean logic, whereas a three-state non-Boolean logic suffices for the studied examples; 3), studied CRMs of the intact phages seemed to have a similar GRF topology (the number of plateaus and peaks corresponding to different expression regimes); we hypothesize that functionally equivalent CRMs might have topologically equivalent GRFs for a larger class of genetic systems; and 4) within a given GRF class, a set of mechanistic-to-mathematical transformations has been identified, which allows shaping the GRF before carrying out a system-level analysis.
Teif
Vladimir B
VB
Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum and BioQuant, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. Vladimir.Teif@bioquant.uni-heidelberg.de
D001435:Bacteriophages / Q000378:metabolism*; D001665:Binding Sites; D004247:DNA / Q000737:chemistry; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics; D005786:Gene Expression Regulation; D007700:Kinetics; D007780:Lacticaseibacillus casei / Q000235:genetics; D017045:Lactococcus / Q000235:genetics; D008242:Lysogeny; D008954:Models, Biological; D008962:Models, Theoretical; D015398:Signal Transduction
D004247:DNA; D012321:DNA-Directed RNA Polymerases