zif268

Zif268, also known as EGR1 (early growth response 1), is a zinc finger transcription factor encoded by the human EGR1 gene. In rodents the protein is frequently referred to as Zif268, while in humans it is commonly called EGR1. It is a member of the C2H2-type zinc finger family, characterized by three C2H2 zinc finger domains at the C-terminus and transcriptional activation regions at the N-terminus.

Expression of Zif268 is rapidly and transiently induced by neuronal activity and a variety of stimuli, including growth factors. In neurons, its transcription is triggered by calcium influx through NMDA receptors and other signaling pathways, notably the MAPK/ERK cascade, linking synaptic activity to changes in gene expression.

Zif268 binds GC-rich DNA sequences, with a consensus motif around GCGGGGCG. As a transcription factor, it regulates a broad set of activity-dependent genes involved in synaptic plasticity, learning, and memory, and it contributes to dendritic spine formation and long-term potentiation in the hippocampus. Because its expression closely follows neuronal activation, Zif268 is widely used as an immunohistochemical marker of neuronal activity in neuroscience research.

Beyond the nervous system, EGR1/Zif268 participates in various cellular processes and can influence cell proliferation and differentiation. Its role is context-dependent, acting as a tumor suppressor or promoter in different cancers. The EGR family comprises several related transcription factors (EGR1–EGR4), which share conserved DNA-binding domains and regulatory functions.