EGR1

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 is_associated_with::protein that in humans is encoded by the EGR1 is_associated_with::gene.

EGR-1 is a mammalian is_associated_with::transcription factor. It was also named Krox-24, TIS8, and ZENK. It was originally discovered in mice.

Function
The protein encoded by this gene belongs to the EGR family of Cys2His2-type is_associated_with::zinc finger proteins. It is a is_associated_with::nuclear protein and functions as a transcriptional regulator. The products of target genes it activates are required for differentiation and is_associated_with::mitogenesis. Studies suggest this is a is_associated_with::tumor suppressor gene.

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.

EGR-1 has also been found to regulate the expression of is_associated_with::synaptobrevin II (a protein important for synaptic is_associated_with::exocytosis).

Structure
The DNA-binding domain of EGR-1 consists of three is_associated_with::zinc finger domains of the Cys2His2 type. The amino acid structure of the EGR-1 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 is_associated_with::alpha helix (there is no zero). The residues marked 'x' are not part of the zinc fingers, but rather serve to connect them all together.

The is_associated_with::crystal structure of is_associated_with::DNA bound by the zinc finger domain of EGR-1 was solved in 1991, which greatly aided early research in zinc finger DNA-binding domains.

The human EGR-1 protein contains (in its unprocessed form) 543 amino acids with a molecular weight of 57.5 is_associated_with::kDa, and the gene is located on the is_associated_with::chromosome 5.

DNA Binding Specificity
EGR-1 binds the DNA sequence 5'-GCG TGG GCG-3' (and similar ones like 5'-GCG GGG GCG-3'). The f1 position 6 binds the 5' G (the first base count from the left); the f1 position 3 to the second base (C); f1 position -1 binds to the third position (G); f2 position 6 to the fourth base (T); and so on.

Interactions
EGR-1 has been shown to interact with is_associated_with::NAB1, is_associated_with::CEBPB, is_associated_with::EP300, is_associated_with::CREB-binding protein, is_associated_with::PSMA3 and is_associated_with::P53.