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Evolution of DNA binding motifs and operators.
Siddhartha Roy1, Ashutosh Sahu, Sankar Adhya
1Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Building 37, Room 5138, 37 Convent Drive MSC 4264, Bethesda, MD 20892-4264, USA.
Gene
|June 1, 2002
Summary
Gene regulatory proteins with helix-turn-helix motifs often contain operator sequences within their DNA-binding regions, suggesting a common evolutionary origin for auto-regulation in these DNA-binding proteins.
Area of Science:
- Molecular Biology
- Genetics
- Evolutionary Biology
Background:
- Gene regulatory proteins utilize DNA-binding motifs, such as the helix-turn-helix (HTH), to control gene expression.
- The GalS protein, a known HTH regulator, possesses a functional operator sequence within its HTH-encoding DNA region.
Purpose of the Study:
- To investigate the prevalence of operator-like sequences within the DNA-binding regions of other regulatory proteins.
- To explore the evolutionary implications of these findings for the auto-regulation of DNA-binding proteins.
Main Methods:
- Bioinformatic search for operator-like sequences in DNA sequences encoding HTH motifs of various regulatory proteins.
- Comparative analysis of sequence data and known auto-regulation status of identified proteins.
Main Results:
- Five regulatory proteins (DeoR, CytR, LRP, LuxR, PurR) were found to have operator or operator-like sequences within their HTH-encoding DNA.
- Most of these proteins, including GalS, exhibit auto-regulation, with DeoR being an exception requiring further investigation.
- Seven other HTH proteins lacked operator-like sequences in their HTH-encoding regions, and most were not auto-regulated, except for MerR.
Conclusions:
- The presence of operator-like sequences within DNA-binding motifs suggests a potential common ancestral origin for auto-regulation in DNA-binding proteins.
- This finding supports the hypothesis that DNA-binding sites within gene segments encoding DNA-binding motifs may have evolved to facilitate auto-regulation.