Functional Overexpression of Vomeronasal Receptors Using a Herpes Simplex Virus Type 1 (HSV-1)-Derived Amplicon.

Benjamin Stein,Frank Zufall,Pablo Chamero,Pablo Chamero,Pablo Chamero,Pablo Chamero,Trese Leinders-Zufall,María Teresa Alonso,María Teresa Alonso,Johannes Reisert

doi:10.1371/journal.pone.0156092

Abstract

In mice, social behaviors such as mating and aggression are mediated by pheromones and related chemosignals. The vomeronasal organ (VNO) detects olfactory information from other individuals by sensory neurons tuned to respond to specific chemical cues. Receptors expressed by vomeronasal neurons are implicated in selective detection of these cues. Nearly 400 receptor genes have been identified in the mouse VNO, but the tuning properties of individual receptors remain poorly understood, in part due to the lack of a robust heterologous expression system. Here we develop a herpes virus-based amplicon delivery system to overexpress three types of vomeronasal receptor genes and to characterize cell responses to their proposed ligands. Through Ca2+ imaging in native VNO cells we show that virus-induced overexpression of V1rj2, V2r1b or Fpr3 caused a pronounced increase of responsivity to sulfated steroids, MHC-binding peptide or the synthetic hexapeptide W-peptide, respectively. Other related ligands were not recognized by infected individual neurons, indicating a high degree of selectivity by the overexpressed receptor. Removal of G-protein signaling eliminates Ca2+ responses, indicating that the endogenous second messenger system is essential for observing receptor activation. Our results provide a novel expression system for vomeronasal receptors that should be useful for understanding the molecular logic of VNO ligand detection. Functional expression of vomeronasal receptors and their deorphanization provides an essential requirement for deciphering the neural mechanisms controlling behavior.

Highlights

In mice and other terrestrial vertebrates, social behavior and reproductive physiology are mediated by chemosignals that are recognized by the olfactory systems [1,2]
Herpes simplex virus type-1 (HSV-1) Amplicon-Mediated Expression of Vomeronasal Receptors detected in the vomeronasal organ (VNO) by sensory neurons that express three major families of G protein-coupled receptors (GPCRs), vomeronasal receptors (VRs) type 1 and 2 (V1Rs and V2Rs), and formyl peptide receptors (Fprs) [3,4,5,6]
By choosing a selected member from each of the three major vomeronasal receptor families–V1rj2, V2r1b and Fpr3 –we demonstrate here that virus-induced overexpression in native VNO cells is a useful approach to characterize and identify receptor-ligand pairs underlying molecular sensing in the VNO

Summary

Introduction

In mice and other terrestrial vertebrates, social behavior and reproductive physiology are mediated by chemosignals that are recognized by the olfactory systems [1,2]. HSV-1 Amplicon-Mediated Expression of Vomeronasal Receptors detected in the vomeronasal organ (VNO) by sensory neurons that express three major families of G protein-coupled receptors (GPCRs), vomeronasal receptors (VRs) type 1 and 2 (V1Rs and V2Rs), and formyl peptide receptors (Fprs) [3,4,5,6]. These receptors have been implicated in recognizing a highly diverse collection of ligands and initiating transduction in vomeronasal sensory neurons (VSNs). Gene transfer and functional expression of cloned vomeronasal receptors is a fundamental requirement for providing a causal link between receptor activation and ligand recognition and understanding the chemical receptive properties that, in turn, provide the foundation for neural coding of social odorants

Methods

Results

Conclusion