1: J Biol Chem. 1997 Jun 27;272(26):16490-7. 

hMAF, a small human transcription factor that heterodimerizes specifically with
Nrf1 and Nrf2.

Marini MG, Chan K, Casula L, Kan YW, Cao A, Moi P.

Istituto di Clinica e Biologia dell'Eta Evolutiva, Universita di Cagliari,
Cagliari 09121, Italy.

A 1.6-kilobase pair full-length cDNA encoding a transcription factor homologous
to the Maf family of proteins was isolated by screening a K562 cDNA library with
the NFE2 tandem repeat probe derived from the globin locus control region. The
protein, which was designated hMAF, contains a basic DNA binding domain and an
extended leucine zipper but lacks any recognizable activation domain. Expressed
in vitro, the hMAF protein is able to homodimerize in solution and band-shift
the NFE2 tandem repeat probe. In addition to homodimers, hMAF can also form high
affinity heterodimers with two members of the NFE2/CNC-bZip family (Nrf1 and
Nrf2) but not with a third family member, p45-NFE2. Although hMAF/hMAF
homodimers and hMAF/Nrf1 and hMAF/Nrf2 heterodimers bind to the same NFE2 site,
they exert functionally opposite effects on the activity of a linked
gamma-globin gene. In fact, whereas all hMAF/CNC-bZip heterodimers stimulate the
activity of a gamma-promoter reporter construct in K562 cells, the association
into homodimers that is induced by overexpressing hMAF inhibits the activity of
the same construct. Thus variations in the expression of hMAF may account for
the modulation in the activity of the genes that bear NFE2 recognition sites.

PMID: 9195958 [PubMed - indexed for MEDLINE]


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