A framework for exploring functional variability in olfactory receptor genes.
BACKGROUND
Olfactory receptors (ORs) are the largest gene family in mammalian genomes. Since nearly all OR genes are orphan receptors, inference of functional similarity or differences between odorant receptors typically relies on sequence comparisons. Based on the alignment of entire coding region sequence, OR genes are classified into families and subfamilies, a classification that is believed to be a proxy for OR gene functional variability. However, the assumption that overall protein sequence diversity is a good proxy for functional properties is untested.


METHODS
Here, we propose an alternative sequence-based approach to infer the similarities and differences in OR binding capacity. Our approach is based on similarities and differences in the predicted binding pockets of OR genes, rather than on the entire OR coding region.


CONCLUSIONS
Interestingly, our approach yields markedly different results compared to the analysis based on the entire OR coding-regions. While neither approach can be tested at this time, the discrepancy between the two calls into question the assumption that the current classification reliably reflects OR gene functional variability.
Man
Orna
O
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel. orna.man@weizmann.ac.il
Willhite
David C
DC
Crasto
Chiquito J
CJ
Shepherd
Gordon M
GM
Gilad
Yoav
Y
D000595:Amino Acid Sequence; D000818:Animals; D016000:Cluster Analysis; D014644:Genetic Variation; D045782:Hemiterpenes; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009812:Odorants; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D010421:Pentanoic Acids / Q000737:chemistry; D010802:Phylogeny; D018035:Receptors, Odorant / Q000145:classification / Q000235:genetics*; D016415:Sequence Alignment
D045782:Hemiterpenes; D010421:Pentanoic Acids; D018035:Receptors, Odorant; C008216:isovaleric acid