Probing the target search of DNA-binding proteins in mammalian cells using TetR as model searcher.

ABSTRACT: Many cellular functions rely on DNA-binding proteins finding and associating to specific sites in the genome. Yet the mechanisms underlying the target search remain poorly understood, especially in the case of the highly organized mammalian cell nucleus. Using as a model Tet repressors (TetRs) searching for a multi-array locus, we quantitatively analyse the search process in human cells with single-molecule tracking and single-cell protein-DNA association measurements. We find that TetRs explore the nucleus and reach their target by 3D diffusion interspersed with transient interactions with non-cognate sites, consistent with the facilitated diffusion model. Remarkably, nonspecific binding times are broadly distributed, underlining a lack of clear delimitation between specific and nonspecif

SUBMITTER: Normanno D 

PROVIDER: S-EPMC4507003 | biostudies-literature | 2015 Jul

REPOSITORIES: biostudies-literature