Specificity-determining DNA triplet code for positioning of human pre-initiation complex

TL;DR

This study uncovers a nonconsensus DNA triplet code that influences the positioning of the human pre-initiation complex, challenging the idea that only consensus motifs determine transcription factor binding.

Contribution

It reveals a novel statistical DNA triplet code that guides PIC positioning, providing new insights into transcriptional regulation mechanisms.

Findings

Identified non-random triplet patterns correlating with PIC binding

Analyzed triplet enrichment/depletion near TSS

Proved nonconsensus DNA code influences PIC positioning

Abstract

The notion that transcription factors bind DNA only through specific, consensus binding sites has been recently questioned. In a pioneering study by Pugh and Venters no specific consensus motif for the positioning of the human pre-initiation complex (PIC) has been identified. Here, we reveal that nonconsensus, statistical, DNA triplet code provides specificity for the positioning of the human PIC. In particular, we reveal a highly non-random, statistical pattern of repetitive nucleotide triplets that correlates with the genome-wide binding preferences of PIC measured by Chip-exo. We analyze the triplet enrichment and depletion near the transcription start site (TSS) and identify triplets that have the strongest effect on PIC-DNA nonconsensus binding. Our results constitute a proof-of-concept for a new design principle for protein-DNA recognition in the human genome, which can lead to a better mechanistic understanding of transcriptional regulation.