Neural Specific Expression of the m4 Muscarinic Acetylcholine Receptor Gene Is Mediated by a RE1/NRSE-type Silencing Element

Abstract

Muscarinic receptor genes are members of the G-protein receptor superfamily that, with the inclusion of the odorant receptors, is believed to contain over a thousand members. Each member of this superfamily, which has been studied to date, appears to have a distinct pattern of expression, but little work has been done on the regulation of these complex expression patterns. We have recently isolated the rat m4 muscarinic receptor gene and identified a genomic 1520-nucleotide sequence that appeared capable of directing cell-specific expression (Wood, I. C., Roopra. A., Harrington, C., and Buckley, N. J. (1995) J. Biol. Chem. 270, 30933-30940). In the present study we have constructed a set of deletion promoter constructs to more closely define the DNA elements that are responsible for m4 gene expression. We have found that deletion of a RE1/NRSE silencer element between nucleotides -574 and -550, similar to that found in other neural specific genes, results in activation of reporter expression in non-m4-expressing cells. Gel mobility shift analysis has shown that a protein present in nonexpressing cells is capable of binding to this element and is probably the recently identified neural silencer, REST/NRSF. Of the constitutively active proximal promoter only a tandem Sp-1 site appears to recruit DNA binding proteins that are present in all cells tested. This represents the first report documenting the role of this silencer in regulating expression of a member of the G-protein receptor family.

Transcriptional control and the role of silencers in transcriptional regulation in eukaryotes

“…EMSA, RNase protection assays and transient transfection assays with reporter-gene deletion constructs of promoters from the rat m4 muscarinic acetylcholine receptor gene (mAChR) [138,142], the human synapsin I gene [139] and the rat dopamine β-hydroxylase gene [137] have recently revealed the presence of cell-specific silencers that were identified as NRSEs by sequence. In all three systems, NRSE was shown to silence promoter expression in several non-neuronal cells, but not in neuronal cells.…”

Functional significance of repressor element 1 silencing transcription factor (REST) target genes in pancreatic beta cells

“…Target genes possess a 21 bp cis element called RE-1 or neuron restrictive silencer element, to which REST binds to inhibit expression. Initial studies indicated that many REST target genes contribute to synaptic plasticity/remodelling, inasmuch as REST regulates the expression of synaptic vesicle proteins [4], voltagesensitive ion channels [2] and neurotransmitter receptors [5,6]. However, increasing evidence suggests that the significance of the REST/RE-1 system is diverse in embryonic and adult cells and depends on the range of target genes that REST interacts with.…”

Repressor Element Silencing Transcription Factor/Neuron-restrictive Silencing Factor (REST/NRSF) Can Act as an Enhancer as Well as a Repressor of Corticotropin-releasing Hormone Gene Transcription

“…The repressor element silencing transcription factor (REST/NRSF) has been shown in a variety of genetic contexts to repress transcriptional activity via binding to this element (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). It was originally thought that the REST/NRSF-RE-1/ NRSE system served as a molecular switch that helped distinguish neural from non-neural cell types, as the repression was thought to occur in non-neural cells, which contain REST/ NRSF, but not in neural cells, which either lack or contain only relatively low levels of REST/NRSF (6,10,13,16).…”