Tristability in cancer-associated microRNA-TF chimera toggle switch
Mingyang Lu1, Mohit Kumar Jolly, Ryan Gomoto
1Center for Theoretical Biological Physics, ‡Department of Bioengineering, §Department of Chemistry, ∥Department of Physics and Astronomy, ⊥Department of Biochemistry and Cell Biology, Rice University , Houston, Texas 77005-1827, United States.
The Journal of Physical Chemistry. B
|May 18, 2013
Summary
This study explores gene circuits controlling cell fate, finding that microRNA-transcription factor switches can also create three stable states, similar to transcription factor-only switches. This expands our understanding of cell differentiation and cancer development.
Area of Science:
- Developmental Biology
- Cancer Biology
- Systems Biology
- Molecular Biology
Background:
- Cell fate decisions are crucial in development and cancer, often regulated by gene circuits like toggle switches.
- Classical toggle switches involve two mutually inhibiting transcription factors (TFs), while chimera switches involve a microRNA (miRNA) and a TF.
- While TF-TF switches can exhibit tristability (three metastable states), the role of chimera switches in this phenomenon is unclear.
Purpose of the Study:
- To develop a generalized framework for both TF-TF and miRNA-TF self-activating toggle switches (SATS).
- To investigate whether chimera SATSs can also exhibit tristability.
- To compare the dynamics of miRNA-TF SATS with TF-TF SATS.
Main Methods:
- Developed a generalized mathematical framework for TF-TF SATS and miRNA-TF chimera SATS.
- Modeled dynamics based on TF-promoter and miRNA-mRNA binding/unbinding kinetics.
- Analyzed the nonlinear effects of translational silencing by miRNAs versus transcriptional repression by TFs.
Main Results:
- Demonstrated that chimera SATSs, like TF-TF SATSs, can exhibit tristability.
- Showed that miRNA-TF SATS dynamics differ qualitatively from TF-TF SATS dynamics.
- Highlighted distinct nonlinear effects between miRNA-mediated translational silencing and TF-mediated transcriptional repression.
Conclusions:
- Chimera toggle switches can generate additional metastable states, expanding the repertoire of cell fate regulation.
- The distinct mechanisms of miRNA and TF regulation lead to qualitatively different circuit dynamics.
- Findings offer insights into cell fate decisions in both normal development and cancer, particularly the existence of intermediate cell types.
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