MAFG, also known as transcription factor MafG, belongs to the Maf family. Since they lack a putative transactivation domain, the small Mafs behave as transcriptional repressors when they dimerize among themselves. However, they seem to serve as transcriptional activators by dimerizing with other (usually larger) basic-zipper proteins and recruiting them to specific DNA-binding sites. Small Maf proteins heterodimerize with Fos and may act as competitive repressors of the NF-E2 transcription factor. Recombinant human MAFG protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.