The MAF protein is located on the MAF gene, which is in turn found on chromosome 16q22-q23. MAF (c-MAF) was first found and thereby cloned in chickens as the homolog of the founding member of the family, which is known as the viral v-MAF gene, and thereby encoded by the virus that in turn induces Musculoaponeurotic Fibrosarcoma. That is where the MAF gets its name, as well as that being an important part of understanding it as a protein.
The MAF gene encodes two separate isoforms which are in turn generated through a process of alternative splicing. These two protein isoforms are known as the MAF short form and the MAF long form, these comprising the two main types of MAF. MAF is like all large Maf proteins in that it contains an amino-terminal transactivation domain along with a carboxy-terminal b-ZIP DNA binding domain. The large MAF proteins stimulate the transcription of the genes they have targeted, by binding to two types of sequences.
The MAF short form is translated from the longest mRNA, which is to be encoded by one exon. At the same time, the longest is encoded by two exons. These two products differ significantly and visibly in their carboxy terminal part, with the long form in particular seen to be containing 30 extra amino-acids.
You can find MAF expressed in many tissues in organisms, from the kidneys to lens and neural tissue.