Transcription factor involved in transcription regulation during lens development, including that of crystallin and filensin/BFSP1 genes (PubMed:9525857). Binds to CRE-type MARE 5'-TGCTGACGTCAGCA-3' and TRE-type MARE 5'-TGCTGACTCAGCA-3' DNA sequences (PubMed:12970735). Forms homodimers or heterodimers. May interact (via leucine-zipper domain) with MAFB. May interact with FOS and JUN. Interacts with PCAF; this interaction impairs MAFA ubiquitination. First detected in the lens placode at stage 11, when the head ectoderm makes contact with the optic vesicle. The expression remains restricted to the invaginating lens placode, and subsequently to the developing lens vesicle. In 8-day old embryo, almost exclusively expressed in lens with very weak expression in brain. Belongs to the bZIP family. Maf subfamily.