Oregon Health & Science University
Nervous system development involves complex extrinsic and intrinsic signaling pathways that precisely coordinate the maintenance of a progenitor pool and the orderly acquisition of a neuronal fate by systematically regulating the expression of genes. This process is mediated by transcription factors. Among the ones that play an essential role in this process is REST, the RE1 silencing transcription factor. REST regulates a large number of genes encoding proteins that are fundamental for neuronal traits by binding to a conserved 23bp element present in its target genes. REST is highly expressed in stem cells where it impedes the expression of those neuronal genes. As cells start to differentiate, REST is downregulated and therefore repression is lifted and neurons acquire their identity. Early studies suggested this downregulation occurs at embryonic day 10.5, and after that, REST was no longer present. However, a few papers have challenged this view and showed that REST may be expressed in adult brain.
In this thesis work, I sought to confirm and expand the notion that REST is expressed in the adult brain. In doing so, I developed rat monoclonal and polyclonal antibodies to confidently detect mouse REST protein in frozen brain tissue. I also used biochemical approaches, confocal microscopy, and a knockout mouse model to demonstrate that REST mRNA, protein, and endogenous promoter activity are found in several areas of the brain, including cortex, cerebellum, hippocampus, olfactory bulb, brain stem, among others. Importantly, REST binds to the chromatin of target genes and also regulates their expression in a brain-area specific manner in the adult brain. Lastly, a great deal of recent attention has been placed on the potential role of REST in Alzheimer’s disease. In this thesis, I provide evidence REST levels maybe regulated in an age-dependent manner in both mouse and human brains.
The major conclusion of this dissertation is that the RE1 silencing transcription factor, REST, is indeed expressed in adult brain. Although we do not know the precise function REST plays, this study opens up an entirely new avenue that should lead to a better understanding of its role in mature neurons, and ultimately, an understanding of neurological disorders and potential therapeutics.
Neuroscience Graduate Program
School of Medicine
Mullendorff, Karin Andrea, "Study of the master neuronal regulator REST in adult brain" (2014). Scholar Archive. 3502.
Available for download on Tuesday, June 20, 2017