Reactome | Expression of Olfactory Receptor

Expression of Olfactory Receptor

Stable Identifier

R-HSA-9752950

Type

Reaction [omitted]

Species

Homo sapiens

Compartment

nucleoplasm, endoplasmic reticulum membrane

ReviewStatus

5/5

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An olfactory receptor (OR) gene is transcribed to yield mRNA and the mRNA is translated to yield OR protein initially located in the endoplasmic reticulum membrane and then translocated through the Golgi to the plasma membrane (Durante et al. 2020, Olender et al. 2016, and inferred from mouse homologs). Humans contain 857 possible OR genes, however the number of human OR genes that are expressed and functional is the subject of current research. Durante et al. (2020) found 143 ORs expressed in olfactory neurons by single cell sequencing. Olender et al. (2016) found 346 intact human OR genes were expressed in at least 1 of 14 individuals. (About 61% of 466 OR pseudogenes also showed some expression.) Verbeurgt et al. (2014) found 273 OR genes were expressed above 5 copies per ng RNA in at least 1 of 26 individuals. Each mature olfactory sensory neuron expresses only one olfactory receptor (OR) (inferred from mouse homologs). LHX2, LDB1, and EBF1 bind intergenic olfactory enhancers and activate transcription (inferred from mouse homologs). Deletion of LHX2 causes loss of OR expression (inferred from mouse homologs). Heterochromatic silencing governed by EHMT2 (KMT1C, G9a) and EHMT1 (KMT1D, GLP) is required for singular receptor expression and produces a diversity of OR gene expression (inferred from mouse homologs). Olfactory enhancers interact interchromosomally to activate transcription of an OR gene (inferred from mouse homologs).

Literature References

PubMed ID	Title	Journal	Year
24800820	Profiling of olfactory receptor gene expression in whole human olfactory mucosa Verbeurgt, C, Wilkin, F, Tarabichi, M, Gregoire, F, Dumont, JE, Chatelain, P	PLoS One	2014
27515280	The human olfactory transcriptome Olender, T, Keydar, I, Pinto, JM, Tatarskyy, P, Alkelai, A, Chien, MS, Fishilevich, S, Restrepo, D, Matsunami, H, Gilad, Y, Lancet, D	BMC Genomics	2016
32066986	Single-cell analysis of olfactory neurogenesis and differentiation in adult humans Durante, MA, Kurtenbach, S, Sargi, ZB, Harbour, JW, Choi, R, Kurtenbach, S, Goss, GM, Matsunami, H, Goldstein, BJ	Nat Neurosci	2020