Immediate early gene

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An immediate early gene (abbreviated IEG to German about immediate early gene ) is a gene that within a few minutes after the stimulation of a cell transcribed is. The transcription of these genes is only temporary and ends a few minutes after stimulation. This stimulation can take place through growth factors , neurotransmitters or electrical excitation of the cells. A mediator of the signal cascade triggered by growth factors is the transcription factor serum response factor (SRF), which was discovered in 1986 by Richard Treisman . SRF binds to the CArG box, a conserved region in the promoter region of many genes, including that of c-Fos and other IEGs.

IEGs are characterized by their low expression without stimulation, the rapid, transient transcriptional induction by extracellular stimulation that is independent of new protein synthesis, and the subsequent protein synthesis-dependent shutdown of transcription. They belong to the primary response genes (in German about direct response genes ). The short half-life of the mRNA is also typical .

The first immediate early genes discovered were predominantly transcription factors ; They include, for example, members of the Fos and Jun gene families as well as Myc and Zif268 . They lead to the expression of protein synthesis-dependent secondary response genes. In the meantime a number of IEGs have been characterized whose gene products themselves act as effector proteins. These include growth factors ( BDNF , β-activin ), proteins that are involved in neuronal signal transmission ( Homer 1a , Rheb ), metabolic enzymes ( cyclooxygenase-2 ) and cell membrane proteins ( Arcadlin , Narp ).

In addition to the IEGs there is also delayed (to German delayed) primary response genes, takes a few hours the protein synthesis-independent induction .

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  1. ↑ M. Sheng, ME Greenberg: The regulation and function of c-fos and other immediate early genes in the nervous system. In: Neuron. Volume 4, Number 4, April 1990, pp. 477-485, PMID 1969743 (review).
  2. ^ R. Treisman: Identification of a protein-binding site that mediates transcriptional response of the c-fos gene to serum factors. In: Cell. Volume 46, Number 4, Aug 1986, pp. 567-574, PMID 3524858 .
  3. ↑ a b J. W. Tullai, ME Schaffer, S. Mullen Brock, G. Sholder, p Kasif, GM Cooper: immediate early and delayed primary response genes are distinct in function and genomic architecture. In: The Journal of biological chemistry. Volume 282, number 33, August 2007, pp. 23981-23995, doi : 10.1074 / jbc.M702044200 , PMID 17575275 , PMC 2039722 (free full text).