title: Identification of novel post-transcriptional features in olfactory receptor family mRNAs.
abstract: Olfactory receptor (Olfr) genes comprise the largest gene family in mice. Despite their importance in olfaction, how most Olfr mRNAs are regulated remains unexplored. Using RNA-seq analysis coupled with analysis of pre-existing databases, we found that Olfr mRNAs have several atypical features suggesting that post-transcriptional regulation impacts their expression. First, Olfr mRNAs, as a group, have dramatically higher average AU-content and lower predicted secondary structure than do control mRNAs. Second, Olfr mRNAs have a higher density of AU-rich elements (AREs) in their 3'UTR and upstream open reading frames (uORFs) in their 5 UTR than do control mRNAs. Third, Olfr mRNAs have shorter 3' UTR regions and with fewer predicted miRNA-binding sites. All of these novel properties correlated with higher Olfr expression. We also identified striking differences in the post-transcriptional features of the mRNAs from the two major classes of Olfr genes, a finding consistent with their independent evolutionary origin. Together, our results suggest that the Olfr gene family has encountered unusual selective forces in neural cells that have driven them to acquire unique post-transcriptional regulatory features. In support of this possibility, we found that while Olfr mRNAs are degraded by a deadenylation-dependent mechanism, they are largely protected from this decay in neural lineage cells.
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0695, USA.
authors.forename: Eleen Y
authors.initials: EY
authors.lastname: Shum
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0695, USA.
authors.forename: Josh L
authors.initials: JL
authors.lastname: Espinoza
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0695, USA.
authors.forename: Madhuvanthi
authors.initials: M
authors.lastname: Ramaiah
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0695, USA Institute of Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA mfwilkinson@ucsd.edu.
authors.forename: Miles F
authors.initials: MF
authors.lastname: Wilkinson
mesh_terms: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D005260:Female; D020869:Gene Expression Profiling; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000378:metabolism; D005810:Multigene Family; D009831:Olfactory Mucosa / Q000378:metabolism*; D016366:Open Reading Frames; D012323:RNA Processing, Post-Transcriptional; D020871:RNA Stability; D012333:RNA, Messenger / Q000737:chemistry* / Q000378:metabolism; D018035:Receptors, Odorant / Q000235:genetics* / Q000378:metabolism; D017423:Sequence Analysis, RNA
chemical_list: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D035683:MicroRNAs; D012333:RNA, Messenger; D018035:Receptors, Odorant