Specific expression of olfactory binding protein in the aerial olfactory cavity of adult and developing Xenopus.
Olfactory binding proteins (OBP), commonly associated with aerial olfaction, are found in the olfactory mucus of mammals but have never been identified in fish. It is still not clear whether the presence of OBP in aerial olfactory systems is due to phylogenetic or to functional differences linked to the adaptation of the olfactory system to an aerial environment. To test this alternative, the olfactory system of Xenopus offers a unique opportunity because it includes two olfactory cavities, one of which is thought to be devoted to aquatic olfaction and the other to aerial olfaction. We therefore purified and cloned OBPs in two Xenopus species. Xenopus laevis OBP (XlaeOBP) and Xenopus tropicalis OBP (XtroOBP) exhibit 158 and 160 amino acids, respectively, sharing 89 residues. cRNA probes allowed us to demonstrate that XlaeOBP and XtroOBP are expressed at the level of Bowman's gland specifically in the aerial olfactory cavity, as confirmed using anti-XlaeOBP antiserum. OBP mRNA transcription occurs early during metamorphosis, as early as stage 57. This is the first study to demonstrate that OBPs are exclusively present in the aerial chamber and are only expressed as the tadpole becomes an adult in species which possess both aquatic and aerial olfactory organs.
Millery
Julie
J
Centre Européen des Sciences du Goût, CNRS UMR 5170, 15 Rue Hugues Picardet, 21000 Dijon, France.
Briand
Loïc
L
Bézirard
Valérie
V
Blon
Florence
F
Fenech
Claire
C
Richard-Parpaillon
Laurent
L
Quennedey
Brigitte
B
Pernollet
Jean-Claude
JC
Gascuel
Jean
J
D000375:Aging / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D001483:Base Sequence; D001923:Brain Chemistry / Q000502:physiology*; D003001:Cloning, Molecular; D015151:Immunoblotting; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007814:Larva; D008969:Molecular Sequence Data; D009093:Mucus / Q000737:chemistry; D009296:Nasal Cavity / Q000737:chemistry; D012333:RNA, Messenger / Q000096:biosynthesis; D018035:Receptors, Odorant / Q000096:biosynthesis*; D013045:Species Specificity; D014981:Xenopus / Q000378:metabolism*; D029867:Xenopus Proteins / Q000096:biosynthesis*; D014982:Xenopus laevis / Q000378:metabolism
C506805:OBP protein, Xenopus; D012333:RNA, Messenger; D018035:Receptors, Odorant; D029867:Xenopus Proteins