REST4 is a neuron specific truncated form of the transcription factor REST/NRSE derived by alternative splicing. REST4 was previously shown to block the repressor activity of REST/NRSF by forming a hetero-oligomer, Shimojo et al. [Mol. Cell. Biol. 19 (1999) 6788-6795]. A series of deletion mutants have now been used to characterize REST4 in terms of its structure and DNA binding. REST4 was found to be O-glycosylated between between residues 87 and 152. Binding of REST4 to the cholinergic RE-1/NRSE was approximately 1/10 to 1/20 as strong as full length REST/NRSF. DNA binding was enhanced by deletion of the first 86 residues and was found to require all four of the C-terminal zinc fingers as well as a twelve amino acid sequence preceding the first of these zinc fingers. REST4 can form homo-oligomers, however only the monomer was found to bind to DNA. REST4 binds to the 3' sequence of the cholinergic NRSE suggesting an anti-parallel orientation of the protein to the DNA.