Encyclopedia of Systems Biology

2013 Edition
| Editors: Werner Dubitzky, Olaf Wolkenhauer, Kwang-Hyun Cho, Hiroki Yokota

Single-Input Module

  • Guangxu JinEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4419-9863-7_464



Single-input module (SIM) was found in the E. coli transcriptional regulation network (Shen-Orr et al. 2002). A single transcription factor, X, regulates a set of operons Z1, …, Zn. X is usually autoregulatory. All regulations are of the same sign (positive or negative). No other transcription factor regulates the operons. Mathematical modeling suggests that SIM can show a detailed temporal program of expression resulting from differences in the activation thresholds of the different genes. Built into this design is a pattern in which the first gene activated is the last one to be deactivated. The SIM motif is found in systems of genes that function stoichiometrically to form a protein assembly (such as flagella) or a metabolic pathway (such as amino-acid biosynthesis).


  1. Shen-Orr SS, Milo R, Mangan S, Alon U (2002) Network motifs in the transcriptional regulation network of Escherichia coli. Nat Genet 31:64–68PubMedCrossRefGoogle Scholar

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© Springer Science+Business Media, LLC 2013

Authors and Affiliations

  1. 1.Systems Medicine and Bioengineering, Bioengineering and Bioinformatics Program, The Methodist Hospital Research InstituteWeill Medical College, Cornell UniversityHoustonUSA