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Manadre, W.

Publications and source records attributed to Manadre, W..

3 recordsLinked to original sources

Beyond motif recognition: Specificity of human transcription factors in yeast

Transcription factors (TFs) bind DNA through sequence-specific DNA-binding domains (DBDs), yet genome-wide analyses show that TFs occupy only a small fraction of their motif occurrences. This raises the question of how TFs distinguish specific targets from the many potential sites in the genome. To investigate determinants of binding specificity beyond the cognate motif and cofactor influences, we measured the binding of 60 human TFs across the budding yeast genome. Although human TFs robustly recognized their motifs, they displayed strong selectivity in site occupancy. Nucleosome abundance explained this selectivity only in part: among the 5-20% of motif sites that were bound, a substantial fraction remained nucleosome covered. Furthermore, TFs recognizing similar motif sequences independently localized to distinct subsets of sites within different promoters. Despite the absence of human-specific cofactors in yeast, both binding stability and genomic preferences depended on largely disordered non-DBD regions. These findings suggest intrinsically disordered regions (IDRs) may therefore direct genome binding TF target recognition across evolutionarily distant genomes. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=124 SRC="FIGDIR/small/721015v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@7db4cborg.highwire.dtl.DTLVardef@e88903org.highwire.dtl.DTLVardef@7b3e11org.highwire.dtl.DTLVardef@127ef29_HPS_FORMAT_FIGEXP M_FIG C_FIG

genetics↗

Protein massively parallel binding assay reveals transcription factor binding determinants

Transcription factors select their genomic binding sites in genomes depending on their DNA binding domain (DBD) but also on regions outside the DBD (nonDBD). However, it remains challenging to define these determinants within nonDBDs and reveal their mechanism of action. Towards this, we introduce here an in-vivo method for parallel analysis of thousands of designed peptides for binding a DNA sequence of interest (Protein Massively Parallel Binding Assay, pMPBA). We apply it to scan the full sequence space of budding yeast TFs and generate a detailed map of DNA localizing determinants. Within the set of predicted DBDs, we reveal a large variation in DNA binding affinities, depending on the family and on different sequence characteristics, including charge. Strong signals were not confined to predicted DBDs but included a considerable fraction of nonDBD peptides, most of which were predicted as intrinsically disordered. pMPBA opens new possibilities for high-throughput analysis of peptide-DNA binding within cells.

genomics↗

Massively Parallel Binding Assay (MPBA) reveals limited transcription factor binding cooperativity, challenging models of specificity

DNA binding domains (DBDs) within transcription factors (TFs) recognize short sequence motifs that are highly abundant in genomes. In vivo, TFs bind only a small subset of motif occurrences, which is often attributed to the cooperative binding of interacting TFs at proximal motifs. However, large-scale testing of this model is still lacking. Here, we describe a novel method allowing parallel measurement of TF binding to thousands of designed sequences within yeast cells and apply it to quantify the binding of dozens of TFs to libraries of regulatory regions containing clusters of binding motifs, systematically mutating all motif combinations. With few exceptions, TF occupancies were well explained by independent binding to individual motifs, with motif cooperation being of only limited effects. Our results challenge the general role of motif combinatorics in directing TF genomic binding and open new avenues for exploring the basis of protein-DNA interactions within cells.

systems biology↗