Abstract
In mammals, odorants and pheromones are detected by hundreds of odorant receptors (ORs) and vomeronasal receptors (V1Rs and V2Rs) expressed by sensory neurons that are respectively located in the main olfactory epithelium and in the vomeronasal organ. Even though these two olfactory systems are functionally and anatomically separate, their sensory neurons show a common mechanism of receptor gene regulation: each neuron expresses a single receptor gene from a single allele. The mechanisms underlying OR and VR gene expression remain unclear. Here we investigated if OR and V1R genes share common sequences in their promoter regions.We conducted a comparative analysis of promoter regions of 39 mouse V1R genes and found motifs that are common to a large number of promoters. We then searched mouse OR promoter regions for motifs that resemble the ones found in the V1R promoters. We identified motifs that are present in both the V1R and OR promoter regions. Some of these motifs correspond to the known O/E like binding sites while others resemble binding sites for transcriptional repressors. We show that one of these motifs specifically interacts with proteins extracted from both nuclei from olfactory and vomeronasal neurons. Our study is the first to identify motifs that resemble binding sites for repressors in the promoters of OR and V1R genes. Analysis of these motifs and of the proteins that bind to these motifs should reveal important aspects of the mechanisms of OR/V1R gene regulation.
Highlights
In mammals, olfactory stimuli are basically detected by sensory neurons located in two different organs: the main olfactory system and the vomeronasal organ (VNO) [1,2,3,4]
Pheromones can be detected by small families of chemosensory receptors, the trace amine-associated receptors (TAARs) [10], which are expressed in the olfactory epithelium, and the formyl peptide receptors (FPRs) [11,12], which are expressed in the VNO
In the present study we analyzed whether odorant receptors (ORs) and V1R gene promoter regions share DNA elements which could be involved in this common mechanism of regulation
Summary
Olfactory stimuli are basically detected by sensory neurons located in two different organs: the main olfactory system and the vomeronasal organ (VNO) [1,2,3,4]. Volatile odorants are detected by odorant receptors (ORs) expressed in the olfactory sensory neurons located in the olfactory epithelium [5]. Pheromones are sensed by two distinct families of vomeronasal receptors, the V1Rs and V2Rs, which are respectively expressed in sensory neurons located in the apical and basal layers of the vomeronasal epithelium [6,7,8,9]. Even though V1Rs show no significant sequence identities with ORs, the pattern of V1R expression shares striking similarities with the expression of ORs. Each olfactory sensory neuron expresses one single odorant receptor (OR) gene out of
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