An odorant-binding protein is abundantly expressed in the nose and in the seminal fluid of the rabbit.
We have purified an abundant lipocalin from the seminal fluid of the rabbit, which shows significant similarity with the sub-class of pheromone carriers "urinary" and "salivary" and presents an N-terminal sequence identical with that of an odorant-binding protein (rabOBP3) expressed in the nasal tissue of the same species. This protein is synthesised in the prostate and found in the seminal fluid, but not in sperm cells. The same protein is also expressed in the nasal epithelium of both sexes, but is completely absent in female reproductive organs. It presents four cysteines, among which two are arranged to form a disulphide bridge, and is glycosylated. This is the first report of an OBP identified at the protein level in the seminal fluid of a vertebrate species. The protein purified from seminal fluid is bound to some organic chemicals whose structure is currently under investigation. We reasonably speculate that, like urinary and salivary proteins reported in other species of mammals, this lipocalin performs a dual role, as carrier of semiochemicals in the seminal fluid and as detector of chemical signals in the nose.
Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy.
Rosa
R
Mastrogiacomo
Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Napoli, Italy.
Chiara
C
D'Ambrosio
Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
Alberto
A
Niccolini
Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy.
Andrea
A
Serra
Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
Angelo
A
Gazzano
Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, Napoli, Italy.
Andrea
A
Scaloni
Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy.
Paolo
P
Pelosi
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004220:Disulfides / Q000737:chemistry; D005260:Female; D006020:Glycopeptides / Q000737:chemistry; D006031:Glycosylation; D008024:Ligands; D008297:Male; D008969:Molecular Sequence Data; D009297:Nasal Mucosa / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011467:Prostate / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011817:Rabbits; D018035:Receptors, Odorant / Q000737:chemistry*; D012661:Semen / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014018:Tissue Distribution; D014357:Trypsin / Q000737:chemistry
D004220:Disulfides; D006020:Glycopeptides; D008024:Ligands; D018035:Receptors, Odorant; C045648:odorant-binding protein; D014357:Trypsin