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It has been shown  that some eukaryotic transcription factors contain a
conserved domain of about 100 amino-acid residues, called the fork head
domain (but also known as a "winged helix"), which is involved in DNA-binding
. Proteins known to contain this domain are listed below.
Drosophila fork head protein (fkh). Fkh is probably a transcription factor
that regulates the expression of genes involved in terminal development.
Drosophila protein crocodile (gene croc) , which is required for the
establishment of head structures.
Drosophila proteins FD2, FD3, FD4, and FD5.
Drosophila proteins sloppy paired 1 and 2 (slp1 and slp2) involved in
Bombyx mori silk gland factor-1 (SGF-1) which regulates transcription of
the sericim-1 gene.
Mammalian transcriptional activators HNF-3-α, -β, and -γ. The
HNF-3 proteins interact with the cis-acting regulatory regions of a number
of liver genes.
Mammalian interleukin-enhancer binding factor (ILF). ILF binds to the
purine-rich NFAT-like motifs in the HIV-1 LTR and the interleukin-2
promoter. ILF may be involved in both positive and negative regulation of
important viral and cellular promoter elements.
Mammalian transcription factor BF-1 which plays an important role in the
establishment of the regional subdivision of the developing brain and in
the development of the telencephalon.
Human HTLF, a protein that binds to the purine-rich region in human T-cell
leukemia virus long terminal repeat (HTLV-I LTR).
Human AFX1 which is involved in a chromosomal translocation that causes
Human FKHR which is involved in a chromosomal translocation that causes
Xenopus XFKH1, a protein essential for normal axis formation.
Caenorhabditis elegans lin-31; involved in the regulation of vulval cell
Yeast HCM1, a protein of unknown function.
The fork domain is highly conserved. We have developed two patterns for its
detection. The first corresponds to the N-terminal section of the domain; the
second is a heptapeptide located in the central section of the domain.
December 2004 / Pattern and text revised.
PROSITE methods (with tools and information) covered by this documentation:
Weigel D., Jaeckle H.
The fork head domain: a novel DNA binding motif of eukaryotic transcription factors?
Haecker U., Kaufmann E., Hartmann C., Juergens G., Knoechel W., Jaeckle H.
EMBO J. 14:5306-5317(1995).
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