Chemosensory Receptor Specificity and Regulation

Abstract

The senses provide a means by which data on the physical and chemical properties of the environment may be collected and meaningfully interpreted. Sensation begins at the periphery, where a multitude of different sensory cell types are activated by environmental stimuli as different as photons and odorant molecules. Stimulus sensitivity is due to expression of different cell surface sensory receptors, and therefore the receptive field of each sense is defined by the aggregate of expressed receptors in each sensory tissue. Here, we review current understanding on patterns of expression and modes of regulation of sensory receptors.

Shared genetic requirements for ATF5 translation in the vomeronasal organ and main olfactory epithelium

“…Based on these premises Dalton proposes that vomeronasal receptors share a similar expression feedback mechanism, to the one described in the MOE, based on ER-resident kinase PERK activation, EIF2α phosphorylation and ATF5 translation. 1 kinase PERK activation, EIF2α phosphorylation and ATF5 translation. To understand if a similar regulatory network, to the one described in olfactory neurons, exist in the VNO Dalton analyzed ATF5 expression in Foxg1Cre;Lsd1 , Foxg1Cre;PERK conditional mutants and in mice carrying a mutated form of eIF2α (eIF2α ) that prevents its phosphorylation and therefore AFT5 expression.…”

“…Mice possess two olfactory organs: the main olfactory epithelium (MOE), which houses olfactory sensory neurons (OSNs), and the vomeronasal organ (VNO), which houses vomeronasal sensory neurons (VSNs) 1 . The MOE is thought largely to function in the detection of odors with no prior or innate behavioral importance, though there are notable exceptions [2][3][4][5] .…”

“…It is neurogenic, giving rise to new VSNs throughout the life of the animal 1,8 . Immature VSNs are located at the tissue margins, or the tips of the crescents, while mature VSNs occupy more central areas.…”

“…Therefore, the choice of receptor(s) to express is considered to be a central gene regulatory decision in VSN development. It is thought that the V1R expressed by a given type I VSN is chosen stochastically during development 1 . In the case of type II VSNs expressing multiple V2R genes, given that the coexpressed receptors (and H2-Mv genes for basal type II VSNs) occur in non-random combinations, it is possible that the initial V2R choice event is stochastic but acts to restrict subsequent V2R or H2-Mv choice events.…”

“…Monogenic OR expression begins with OR gene choice, a complex process involving condensation of OSN chromatin 17 , extensive modification of the OR gene chromatin environment 18,19 , recruitment of cis and trans enhancer elements 20,21 , and cooperation between a number of transcriptional activators 22,23 . OR choice is followed by OR feedback, which functions to preclude further OR gene choice, to promote maturation of the OSN, and to stabilize expression of the chosen OR 1,[24][25][26][27][28][29]30 . Together, OR choice and OR feedback ensure that each mature OSN expresses exactly one OR allele, defining each OSN as a sensitive and unambiguous signaling unit.…”