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Integrated requirement of non‐specific and sequence‐specific DNA binding in Myc‐driven transcription
Author(s) -
Pellanda Paola,
Dalsass Mattia,
Filipuzzi Marco,
Loffreda Alessia,
Verrecchia Alessandro,
Castillo Cano Virginia,
Thabussot Hugo,
Doni Mirko,
Morelli Marco J,
Soucek Laura,
Kress Theresia,
Mazza Davide,
Mapelli Marina,
Beaulieu MarieEve,
Amati Bruno,
Sabò Arianna
Publication year - 2021
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.15252/embj.2020105464
Subject(s) - biology , transcription factor , genetics , dna , sequence motif , dna binding site , gene , protein–dna interaction , transcription (linguistics) , dna binding protein , hmg box , computational biology , binding site , consensus sequence , promoter , gene expression , peptide sequence , linguistics , philosophy
Eukaryotic transcription factors recognize specific DNA sequence motifs, but are also endowed with generic, non‐specific DNA‐binding activity. How these binding modes are integrated to determine select transcriptional outputs remains unresolved. We addressed this question by site‐directed mutagenesis of the Myc transcription factor. Impairment of non‐specific DNA backbone contacts caused pervasive loss of genome interactions and gene regulation, associated with increased intra‐nuclear mobility of the Myc protein in murine cells. In contrast, a mutant lacking base‐specific contacts retained DNA‐binding and mobility profiles comparable to those of the wild‐type protein, but failed to recognize its consensus binding motif (E‐box) and could not activate Myc‐target genes. Incidentally, this mutant gained weak affinity for an alternative motif, driving aberrant activation of different genes. Altogether, our data show that non‐specific DNA binding is required to engage onto genomic regulatory regions; sequence recognition in turn contributes to transcriptional activation, acting at distinct levels: stabilization and positioning of Myc onto DNA, and—unexpectedly—promotion of its transcriptional activity. Hence, seemingly pervasive genome interaction profiles, as detected by ChIP‐seq, actually encompass diverse DNA‐binding modalities, driving defined, sequence‐dependent transcriptional responses.