Chromatin Live Imaging with Genome Editing Techniques: Switching from Scissors to a Lamp

Abstract

Chromatin live imaging integrated with programmable DNA binding proteins derived from genome editing methods opens up the era of spatio-temporal analyses of chromatin dynamics. The DNA binding proteins, including a transcription activator-like effector (TALE) or a nuclease-dead CRISPR-associated protein 9 (dCas9), can be freely designed to bind a specific DNA sequence. Instead of a nuclease for DNA cleavage, a fluorescent protein is fused to TALE or dCAS9 for visualization of chromatin. They enable us to observe the endogenous genomic loci without the fixation of cells, the denaturation of DNA for hybridization and the insertion of exogenous DNA sequences into targeted loci. Using these live imaging systems dependent on the interaction between cis endogenous DNA sequence and trans DNA binding proteins, we can analyze chromatin dynamics in living cells. Multicolor chromatin imaging based on different dCas9 proteins will be a powerful cytogenetical technique instead of multicolor FISH and chromosome painting.