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Updated: May 12, 2025
08:04
DNA Sequence Recognition by DNA Primase Using High-Throughput Primase Profiling
Published on: October 8, 2019
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The Evolution of Sequence Specificity in a DNA Binding Protein Family
Meghna Nandy1, Madhumitha Krishnaswamy2, Mohak Sharda1
1National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India.
Journal of Molecular Biology
|May 1, 2025
Summary
Bacterial transcription factors (TFs) likely evolved from non-specific DNA-binding proteins. The IHF/HU family shows the ancestral HU protein was non-specific, with specific IHF evolving later from a divergent HU branch.
Area of Science:
- Microbiology
- Molecular Biology
- Evolutionary Biology
Background:
- Transcription factors (TFs) regulate gene expression in bacteria, allowing environmental adaptation.
- TFs are not essential for minimal cellular life, raising questions about their evolutionary origins.
- The hypothesis suggests TFs evolved from non-specific DNA-binding proteins.
Purpose of the Study:
- To investigate the evolutionary origins of transcription factors.
- To test the hypothesis that TFs evolved from non-specific DNA-binding proteins.
- To explore the evolutionary trajectory of the IHF/HU family of DNA-binding proteins.
Main Methods:
- Phylogenetic analysis of the IHF/HU protein family.
- In-silico reconstruction of ancestral protein sequences.
- Comparative analysis of DNA-binding specificities between HU and IHF.
Main Results:
- The HUβ subunit is ancient, present from the bacterial root.
- Both IHF subunits evolved later, with diversification in Proteobacteria.
- The ancestral IHF/HU protein was likely non-specific and HU-like.
- IHF evolved from a diverged HU lineage, with subunits acquiring specificity through different evolutionary paths.
Conclusions:
- The IHF/HU family supports the hypothesis that specific DNA-binding proteins evolved from non-specific ancestors.
- IHF subunits evolved distinct molecular mechanisms to achieve DNA sequence recognition.
- Understanding TF evolution provides insights into bacterial adaptation and genome regulation.
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