Epigenetic Remodeling of Delta FosB Protein: Its Role in Regulation of Stress

Abstract

Stress is not affected only on brain but also on the other parts of body like changes in heart rate, blood pressure levels,
circadian rhythm etc. Recent studies have been established that exposure to stress promotes alterations in several
epigenetic characters like histone acetylation and methylation as well as DNA methylation, in various limbic brain
regions. Chromatin remodeling processes are necessary for learning and memory. However, abnormal epigenetic
modifications can lead to cognitive deficits. DeltaFosB (ΔFosB) is protein of Fos family. FosB gene forms FosB and ΔFosB
as product. Increased expression of FosB over ΔFosB in nucleus accumbens (NAc) region of brain protects animals from
the deleterious effects of chronic stress. Moreover, epigenetically, H3K9me2 is enriched at the FosB promoter in NAc of
human depressed patients. FosB has very low life while ∆FosB has exceptionally long life span. Thus persists for long
time in the stress condition and leads to depression and anxiety. It has also been revealed that elevation in ∆FosB level
occurs due to chronic stress condition. The epigenetic factors responsible for stress are governed by ∆FosB expression
level. The expression of ∆FosB in turn depends on the presence of serum response factor (SRF) transcription factor. SRF
transcription factor is encoded by srf gene. To understand the mechanism of stress condition, srf gene can be one of the
promising targets to uncover the problems related to stress conditions.