Electron microscopy reveals toroidal shape of master neuronal cell differentiator REST – RE1-Silencing Transcription factor

The RE1-Silencing Transcription factor (REST) is essential for neuronal differentiation. Here, we report the first 18.5-angstrom electron microscopy structure of human REST. The refined electron map suggests that REST forms a torus that can accommodate DNA double-helix in the central hole. Additionally, we quantitatively described REST binding to the canonical DNA sequence of the neuron-restrictive silencer element. We developed protocols for the expression and purification of full-length REST and the shortened variant REST-N62 produced by alternative splicing. We tested the mutual interaction of full-length REST and the splicing variant REST-N62. Revealed structure-function relationships of master neuronal repressor REST will allow finding new biological ways of prevention and treatment of neurodegenerative disorders and diseases. ### Competing Interest Statement The authors have declared no competing interest. * aa : amino acid(s) bp : base pair(s) CD : circular dichroism CoIP : coimmunoprecipitation DLS : dynamic light scattering EM : electron microscopy IDRs : intrinsically disordered regions kDa : kilodaltons NRSE : neuron-restrictive silencer element NRSF : neuron-restrictive silencer factor PCNA : proliferating cell nuclear antigen RD1/2 : repressor domain 1/2 RE1 : repressor element-1 REST : RE1-silencing transcription factor REST-FL : full-length REST REST-N62 : isoform of REST (also known as REST4 or REST4-S3) ZF : zinc finger