Since they lack a putative transactivation domain, the small Mafs behave as transcriptional repressors when they dimerize among themselves (PubMed:8932385). However, they seem to serve as transcriptional activators by dimerizing with other (usually larger) basic-zipper proteins, such as NFE2L1/NRF1, and recruiting them to specific DNA-binding sites. Interacts with the upstream promoter region of the oxytocin receptor gene (PubMed:16549056, PubMed:8932385). May be a transcriptional enhancer in the up-regulation of the oxytocin receptor gene at parturition (PubMed:10527846). {ECO:0000269|PubMed:10527846, ECO:0000269|PubMed:16549056, ECO:0000269|PubMed:8932385}. This is the function of Ensembl gene identifier ENSG00000185022 (MAFF, MAF bZIP transcription factor F).