EGR-1 (Early growth response protein 1) also known as Zif268 (zinc finger protein 225) or NGFI-A (nerve growth factor-induced protein A) is a protein that in humans is encoded by the EGR1 gene.
EGR-1 is a mammalian transcription factor. It was also named Krox-24, TIS8, and ZENK. It was originally discovered in mice.
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The protein encoded by this gene belongs to the EGR family of C2H2-type zinc-finger proteins. It is a nuclear protein and functions as a transcriptional regulator. The products of target genes it activates are required for differentiation and mitogenesis. Studies suggest this is a tumor suppressor gene.[1]
The DNA-binding domain of Zif268 consists of three zinc finger domains of the Cys2His2 type. The amino acid structure of the Zif268 zinc finger domain is given in this table, using the single letter amino acid code. The fingers 1 to 3 are indicated by f1 - f3. The numbers are in reference to the residues (amino acids) of alpha helix (there is no '0'). The residues marked 'x' are not part of the zinc fingers, but rather serve to connect them all together.
-1 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | x | x | x | x | x | |||||||||||||||||||||||
f1 | M | A | E | E | R | P | Y | A | C | P | V | E | S | C | D | R | R | F | S | R | S | D | E | L | T | R | H | I | R | I | H | T | G | Q | K | P | |
f2 | F | O | C | A | I | ? | ? | C | M | R | N | F | S | R | S | D | H | L | T | T | H | I | A | T | H | T | G | E | K | P | |||||||
f3 | F | A | C | D | I | ? | ? | C | G | R | K | F | A | R | S | D | E | R | K | R | H | T | K | I | H | L | R | Q | K | D |
The crystal structure of DNA bound by the zinc finger domain of Zif268 was solved in 1991, which greatly aided early research in zinc finger DNA-binding domains.[2]
The human Zif268/EGR1 protein contains (in its unprocessed form) 543 amino acids with a molecular weight of 57.5 kDa, and the gene is located on the chromosome 5.
Zif268 binds the DNA sequence 5'-GCG[G/T]GGGCG-3'.[3][4]
It has a distinct pattern of expression in the brain, and its induction has been shown to be associated with neuronal activity. Several studies suggest it has a role in neuronal plasticity.[5]
Zif268 has also been found to regulate the expression of synaptobrevin II (a protein important for synaptic exocytosis).[6]
Zif268 has been shown to interact with NAB1,[7] CEBPB,[8] EP300,[9] CREB-binding protein,[9] PSMA3[10] and P53.[11]
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