Immunological and molecular characterization of Go alpha-like proteins in the Drosophila central nervous system.
The alpha subunits of heterotrimeric G proteins are responsible for the coupling of receptors for a wide variety of stimuli to a number of intracellular effector systems. In the nervous system of vertebrates, high levels of a specific class of G protein (Go alpha) are expressed. The alpha subunit of Go serves as a substrate for modification by pertussis toxin (PTX). In this report, we demonstrate that the Drosophila heads contain high levels of a 40-kDa PTX substrate. Modification of this protein by PTX is modulated in a manner similar to that observed for vertebrate G proteins. The PTX substrate in Drosophila is also recognized specifically by antibodies raised against peptide sequences found specifically in vertebrate Go alpha. Vertebrate Go alpha probes were used to identify a Drosophila cDNA coding for a potential PTX substrate with high sequence identity (82%) to vertebrate Go alpha. An additional cDNA coding for a related Go alpha has also been isolated. The two cDNAs differ only in the 5'-untranslated and amino-terminal regions of the protein. This observation, in addition to Northern analysis, suggests that alternate splicing may generate a variety of Go alpha-like proteins in Drosophila. In situ hybridization of specific probes to tissue sections indicates that the mRNAs coding for Go alpha-like proteins in Drosophila are expressed primarily in neuronal cell bodies and, at lower levels, in the eyes.
Thambi
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NC
Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201.
Quan
F
F
Wolfgang
W J
WJ
Spiegel
A
A
Forte
M
M
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002874:Chromosome Mapping; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D015342:DNA Probes; D004331:Drosophila melanogaster / Q000032:analysis*; D019204:GTP-Binding Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000494:pharmacology; D007163:Immunosorbent Techniques; D008969:Molecular Sequence Data; D009420:Nervous System / Q000032:analysis*; D009693:Nucleic Acid Hybridization; D037342:Pertussis Toxin; D012689:Sequence Homology, Nucleic Acid; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000378:metabolism*
D015342:DNA Probes; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D004247:DNA; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins