TRX-LOGOS - a graphical tool to demonstrate DNA information content dependent upon backbone dynamics in addition to...

Area of Science:

• Computational biology
• Genomics
• Bioinformatics

Background:

• DNA-protein interactions are governed by local biophysical features of the DNA backbone, including shape, charge, and dynamics.
• Traditional sequence logos, based on single nucleobases, do not explicitly represent DNA backbone dynamics, limiting their utility in understanding binding specificity.
• Understanding DNA backbone flexibility is crucial for deciphering the mechanisms of DNA-protein interactions.

Purpose of the Study:

• To introduce TRX-LOGOS, an R software package that extends sequence logo plots to visualize DNA backbone flexibility.
• To integrate Shannon information content with dinucleotide-based conformation shifts, providing a visual measure of intrinsic DNA flexibility.
• To enhance the analysis of regulatory genomics by incorporating dynamic DNA properties.

Main Methods:

• Developed TRX-LOGOS, an R package and Perl wrapper, interfacing with the JASPAR database.
• Calculated Shannon information content based on dinucleotide-based BI-BII conformation shifts in DNA phosphate linkages.
• Applied TRX-LOGOS to analyze transcription factor binding sites from Saccharomyces cerevisiae (Yeastract database) and JASPAR database classifications.
• Utilized MEGA 6.0 for evolutionary analysis and compared SELEX and ChIP-seq data for TP53 binding sites.

Main Results:

• TRX logo plots revealed significantly elevated information content at phosphate linkages compared to nucleobases in flanking regions of transcription factor binding sites.
• Many transcription factor binding signatures are more information-rich at the DNA backbone dynamics level than at the nucleobase sequence level.
• A distinct 3 bp periodic pattern in information content was observed in yeast coding regions, independent of sequence, potentially indicating genetic code organization.

Conclusions:

• TRX-LOGOS effectively visualizes information content at DNA phosphate linkages, crucial for understanding DNA-protein interactions.
• The software provides a valuable tool for situations where DNA backbone dynamics are critical for binding specificity.
• TRX-LOGOS enhances the analysis of regulatory genomics by incorporating dynamic DNA properties into sequence analysis.