The well conserved cysteine-histidine arrangement, C-x(8)-C-x(5)-C-x(3)-H, of
the C3H1-type zinc finger is present in many eukaryotic proteins from yeast to
mammals. In various proteins the C3H1-type zinc finger has been shown to
interact with the 3'-untranslated region of mRNAs (see below). It is very
often present in two copies [1,2].
The structure of the two C3H1-type zinc fingers of the protein TIS11d bound to
its target mRNA has been solved (see <PDB:1RGO>) . The two zinc fingers
fold independently to form small, compact domains connected by the linker
sequence. The polypeptide backbone adopts little regular secondary structure.
In each zinc finger, there is a short α-helix immediately after the first
cysteine ligand and a turn of 3/10 helix between the second and third cysteine
ligands. All amino acid residues that exhibit intermolecular contacts with the
RNA are positioned on a single surface of each zinc finger.
Some proteins known to contain a C3H1-type zinc finger are listed below:
Mammalian tristetraprolin (TTP) proteins, prototype of the C3H1 zinc finger
proteins, inhibit TNF α production from macrophages by destabilizing
its messenger RNA . TTP is a specific RNA-binding protein; the region
encompassing the two C3H1-type zinc fingers recognizes nonameric UUAUUUAUU
sequences present in the 3'-untranslated region (UTR) of TNF α [4,5].
Eukaryotic TIS/CTH family. Regulatory protein involved in regulating the
response to growth factors similar to TTP. The tandem zinc finger domain of
the protein TIS11d binds to the class II AU-rich element (ARE) in the 3'
untranslated region (3' UTR) of target mRNAs and promotes their
deadenylation and degradation .
Eukaryotic U2AG, U2R1, U2R2 proteins, small nuclear ribonucleoproteins
(1 or 2 copies).
Caenorhabditis Elegans PIE1 protein. It is required for specification of
embryonic germ cells lineage and for the lack of mRNA transcription in
these cells (2 copies).
Caenorhabditis Elegans POS-1 protein. A cytoplasmic protein similar to
TIS11, essential for germ line specification in C. elegans (2 copies).
Eukaryotic cleavage and polyadenylation specificity factor subunit 4
(Cpsf4) protein. It plays a key role in pre-mRNA 3'-end formation,
recognizing the AAUAAA signal sequence and interacting with poly(A)
polymerase and other factors to bring about cleavage and poly(A) addition.
Cpsf4 binds RNA polymers with a preference for poly(U) (5 copies).
Schizosaccharomyces pombe ZFS1 protein. It was isolated as a suppressor of
the sterility caused by overexpression of a double-stranded RNase (2
Human Z183 protein, contains one ring finger and one C3H1-type zinc finger.
Mammalian Nucleoporin-like 2, required for the export of mRNAs containing
poly(A) tails from the nucleus into the cytoplasm (1 copy).
The profile we developed covers the entire C3H1-type zinc finger.
June 2008 / First entry.
PROSITE method (with tools and information) covered by this documentation:
Multiple modes of RNA recognition by zinc finger proteins.
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