Binds DNA specifically as homodimer or heterodimer with other PAR factors. Accumulates according to a robust circadian rhythm. Displays only a moderate amplitude in the liver (1.6-fold) and none in the brain. Mice deficient for all three PAR bZIP proteins (DBP, HLF and TEF) display a dramatically shortened life span and are highly susceptible to generalized spontaneous and audiogenic epilepsies (due for example to the noise of a vacuum cleaner) that are frequently lethal. The down-regulation of pyridoxal kinase (Pdxk) expression in these mice may participate in this seizure phenotype. Belongs to the bZIP family. PAR subfamily.