Molecular cloning of five GTP-binding protein cDNA species from rat olfactory neuroepithelium.
Biochemical studies in vertebrate olfactory tissue indicate that certain odorants stimulate adenylyl cyclase in a GTP-dependent manner. Additionally, immunochemical and toxin-labeling studies demonstrate the presence of several GTP-binding protein (G-protein) species in vertebrate olfactory epithelium. To identify the G-protein(s) responsible for olfactory signal transduction, we screened a rat olfactory cDNA library with an oligonucleotide probe and isolated 32 recombinant clones encoding five distinct types of G-protein alpha subunits. The majority of the clones encoded G alpha s, while the remaining clones encoded G alpha o, G alpha i1, G alpha i2, and a novel species, G alpha i3. Messenger RNA corresponding to each G alpha was detectable in all tissues examined; however, the levels for a given G alpha varied in a tissue-specific manner. In olfactory tissue, G alpha s was the most abundant of these messages and in combination with the biochemical studies suggests that G alpha s is the G-protein component of the olfactory signal transduction cascade.
Jones
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Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Reed
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002490:Central Nervous System / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism*; D004262:DNA Restriction Enzymes; D004848:Epithelium / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics*; D005796:Genes; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009833:Olfactory Pathways / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011919:Rats, Inbred Strains; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D015293:Transducin
D008565:Membrane Proteins; D012333:RNA, Messenger; D004247:DNA; D004262:DNA Restriction Enzymes; D019204:GTP-Binding Proteins; D015293:Transducin