Expression profile of ectopic olfactory receptors determined by deep sequencing

Area of Science:

• Genomics
• Molecular Biology
• Physiology

Background:

• Olfactory receptors (ORs) are G-protein coupled receptors crucial for detecting odorants.
• Initially, ORs were believed to be exclusively in the olfactory epithelium.
• Recent findings suggest ectopic expression of some ORs in non-olfactory tissues.

Purpose of the Study:

• To conduct a comprehensive expression analysis of olfactory receptors (ORs) across a wide range of human tissues.
• To investigate the ectopic expression of ORs using advanced Next Generation Sequencing (NGS) techniques.
• To provide a foundational dataset for future functional studies of broadly expressed ORs.

Main Methods:

• Analysis of open-access mRNA-Seq data from the Illumina Body Map project 2.0 (16 human tissues).
• Inclusion of additional OR expression data from a study on human testis.
• Utilized Next Generation Sequencing (NGS) technology for comprehensive transcriptomic analysis.

Main Results:

• Olfactory receptors (ORs) were detected in all 16 analyzed human tissues.
• Broadly expressed ORs, like OR2W3 and OR51E1, were identified in multiple tissues.
• Exclusive expression was noted for some ORs, such as OR4N4 in testis.
• 111 out of 400 OR genes showed expression (FPKM > 0.1) in at least one tissue.
• mRNA expression for several ORs was validated using RT-PCR.

Conclusions:

• Olfactory receptors (ORs) exhibit broad expression patterns across diverse human tissues, extending beyond the olfactory system.
• The findings challenge the traditional view of ORs and support their potential roles in various physiological processes.
• This comprehensive expression map serves as a crucial resource for future research into the non-olfactory functions of ORs.