RESUMO
We present the results of the partial sequencing of over 3,400 expressed sequence tags (ESTs) from human brain cDNA clones, which increases the number of distinct genes expressed in the brain, that are represented by ESTs, to about 6,000. By choosing clones in an unbiased manner, it is possible to construct a profile of the transcriptional activity of the brain at different stages. Proteins that comprise the cytoskeleton are the most abundant; however, a large variety of regulatory proteins are also seen. About half of the ESTs predicted to contain a protein-coding region have no matches in the public peptide databases and may represent new gene families.
Assuntos
Encéfalo/metabolismo , DNA/genética , Transcrição Gênica , Sequência de Aminoácidos , Bases de Dados Factuais , Expressão Gênica , Variação Genética , Humanos , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/genética , Filogenia , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Células Tumorais Cultivadas/metabolismo , Dedos de Zinco/genéticaRESUMO
A human infant brain cDNA library, made specifically for production of expressed sequence tags (ESTs) was evaluated by partial sequencing of over 1,600 clones. Advantages of this library, constructed for EST sequencing, include the use of directional cloning, size selection, very low numbers of mitochondrial and ribosomal transcripts, short polyA tails, few non-recombinants and a broad representation of transcripts. 37% of the clones were identified, based on matches to over 320 different genes in the public databases. Of these, two proteins similar to the Alzheimer's disease amyloid precursor protein were identified.
Assuntos
Precursor de Proteína beta-Amiloide/genética , Encéfalo/metabolismo , DNA Complementar/química , DNA Complementar/genética , Proteínas/genética , Sequência de Aminoácidos , Precursor de Proteína beta-Amiloide/química , Sequência de Bases , Clonagem Molecular , Expressão Gênica , Biblioteca Gênica , Humanos , Lactente , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Proteínas/química , Homologia de Sequência de AminoácidosRESUMO
We have determined the chromosomal assignment of 320 brain expressed genes by studying the segregation of polymerase chain reaction (PCR) products in human rodent somatic cell hybrids and by genetically mapping polymorphic cDNAs using the CEPH (Centre d'Etude du Polymophisme Humaine) reference pedigrees and database. These mapped genes can function as markers on the physical map of the human genome, as well as serve as candidate disease gene loci. Distribution of these genes to the human chromosomes correlates well with the GC content of the chromosomes. However, the distribution of these genes does not correlate well with the cytogenetic length of each chromosome.
Assuntos
Encéfalo/metabolismo , Mapeamento Cromossômico , Cromossomos Humanos , DNA Complementar/genética , Animais , Clonagem Molecular , DNA Complementar/química , Humanos , Células Híbridas , Sistemas de Informação , Escore Lod , Reação em Cadeia da Polimerase/métodos , Polimorfismo GenéticoRESUMO
A database containing mapped partial cDNA sequences from Caenorhabditis elegans will provide a ready starting point for identifying nematode homologues of important human genes and determining their functions in C. elegans. A total of 720 expressed sequence tags (ESTs) have been generated from 585 clones randomly selected from a mixed-stage C. elegans cDNA library. Comparison of these ESTs with sequence databases identified 422 new C. elegans genes, of which 317 are not similar to any sequences in the database. Twenty-six new genes have been mapped by YAC clone hybridization. Members of several gene families, including cuticle collagens, GTP-binding proteins, and RNA helicases were discovered. Many of the new genes are similar to known or potential human disease genes, including CFTR and the LDL receptor.
Assuntos
Caenorhabditis elegans/genética , Genes de Helmintos , Sequência de Aminoácidos , Animais , Clonagem Molecular , Colágeno/genética , DNA/genética , Expressão Gênica , Biblioteca Gênica , Humanos , Dados de Sequência Molecular , Família Multigênica , Homologia de Sequência de Aminoácidos , Especificidade da EspécieRESUMO
Autoantibodies to beta 2-adrenergic receptors have been identified in the serum of one patient with allergic rhinitis ("hay fever") and two patients with asthma. The antibodies precipitate solubilized dog lung beta receptors in an indirect immunoprecipitation assay and inhibit the specific binding of iodine-125-labeled iodohydroxybenzylpindolol to membrane-associated receptors from dog lung, calf lung, and human placenta. Ligand binding to canine heart beta 1 receptors is not affected by the antibodies.
Assuntos
Asma/imunologia , Autoanticorpos , Receptores Adrenérgicos beta/imunologia , Receptores Adrenérgicos/imunologia , Rinite Alérgica Perene/imunologia , Epitopos , Humanos , Pulmão/imunologia , Pulmão/metabolismo , Miocárdio/metabolismo , Pindolol/análogos & derivados , Pindolol/metabolismo , Receptores Adrenérgicos beta/fisiologiaRESUMO
The naturally transformable, Gram-negative bacterium Haemophilus influenzae Rd preferentially takes up DNA of its own species by recognizing a 9-base pair sequence, 5'-AAGTGCGGT, carried in multiple copies in its chromosome. With the availability of the complete genome sequence, 1465 copies of the 9-base pair uptake site have been identified. Alignment of these sites unexpectedly reveals an extended consensus region of 29 base pairs containing the core 9-base pair region and two downstream 6-base pair A/T-rich regions, each spaced about one helix turn apart. Seventeen percent of the sites are in inverted repeat pairs, many of which are located downstream to gene termini and are capable of forming stem-loop structures in messenger RNA that might function as signals for transcription termination.
Assuntos
DNA Bacteriano/genética , Genoma Bacteriano , Haemophilus influenzae/genética , Transformação Bacteriana , Composição de Bases , Sequência de Bases , Mapeamento Cromossômico , Sequência Consenso , Sequência Conservada , DNA Bacteriano/química , Escherichia coli/genética , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Sondas de Oligonucleotídeos , RNA Bacteriano/química , RNA Bacteriano/genética , RNA Mensageiro/química , RNA Mensageiro/genética , Sequências Repetitivas de Ácido Nucleico , Transcrição GênicaRESUMO
A whole-genome restriction map of Deinococcus radiodurans, a radiation-resistant bacterium able to survive up to 15,000 grays of ionizing radiation, was constructed without using DNA libraries, the polymerase chain reaction, or electrophoresis. Very large, randomly sheared, genomic DNA fragments were used to construct maps from individual DNA molecules that were assembled into two circular overlapping maps (2.6 and 0.415 megabases), without gaps. A third smaller chromosome (176 kilobases) was identified and characterized. Aberrant nonlinear DNA structures that may define chromosome structure and organization, as well as intermediates in DNA repair, were directly visualized by optical mapping techniques after gamma irradiation.
Assuntos
Mapeamento de Sequências Contíguas/métodos , Genoma Bacteriano , Cocos Gram-Positivos/genética , Mapeamento por Restrição/métodos , Cromossomos Bacterianos , Dano ao DNA , Reparo do DNA , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Bacteriano/efeitos da radiação , DNA Circular/química , Raios gama , Cocos Gram-Positivos/efeitos da radiação , Processamento de Imagem Assistida por Computador , Microscopia de Fluorescência , Conformação de Ácido Nucleico , Plasmídeos , Tolerância a Radiação , Recombinação GenéticaRESUMO
Mycoplasma genitalium with 517 genes has the smallest gene complement of any independently replicating cell so far identified. Global transposon mutagenesis was used to identify nonessential genes in an effort to learn whether the naturally occurring gene complement is a true minimal genome under laboratory growth conditions. The positions of 2209 transposon insertions in the completely sequenced genomes of M. genitalium and its close relative M. pneumoniae were determined by sequencing across the junction of the transposon and the genomic DNA. These junctions defined 1354 distinct sites of insertion that were not lethal. The analysis suggests that 265 to 350 of the 480 protein-coding genes of M. genitalium are essential under laboratory growth conditions, including about 100 genes of unknown function.
Assuntos
Elementos de DNA Transponíveis , Genes Essenciais , Genoma Bacteriano , Mutagênese Insercional , Mycoplasma/genética , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Aminoacil-tRNA Sintetases/genética , Proteínas de Bactérias/genética , Mapeamento Cromossômico , DNA Polimerase III/genética , DNA Polimerase III/metabolismo , Replicação do DNA/genética , Glicólise/genética , Lipoproteínas/genética , Mycoplasma/metabolismo , Mycoplasma pneumoniae/genética , Mycoplasma pneumoniae/metabolismo , Proteínas Ribossômicas/genética , Transcrição GênicaRESUMO
The complete 1.66-megabase pair genome sequence of an autotrophic archaeon, Methanococcus jannaschii, and its 58- and 16-kilobase pair extrachromosomal elements have been determined by whole-genome random sequencing. A total of 1738 predicted protein-coding genes were identified; however, only a minority of these (38 percent) could be assigned a putative cellular role with high confidence. Although the majority of genes related to energy production, cell division, and metabolism in M. jannaschii are most similar to those found in Bacteria, most of the genes involved in transcription, translation, and replication in M. jannaschii are more similar to those found in Eukaryotes.
Assuntos
Proteínas de Bactérias/genética , DNA Bacteriano/genética , Genoma Bacteriano , Mathanococcus/genética , Sequência de Aminoácidos , Proteínas de Bactérias/química , Composição de Bases , Sequência de Bases , Transporte Biológico/genética , Dióxido de Carbono/metabolismo , Mapeamento Cromossômico , Cromossomos Bacterianos/genética , Replicação do DNA , Bases de Dados Factuais , Metabolismo Energético/genética , Genes Bacterianos , Hidrogênio/metabolismo , Metano/metabolismo , Mathanococcus/fisiologia , Dados de Sequência Molecular , Biossíntese de Proteínas , Análise de Sequência de DNA , Transcrição GênicaRESUMO
The complete genome sequence of Treponema pallidum was determined and shown to be 1,138,006 base pairs containing 1041 predicted coding sequences (open reading frames). Systems for DNA replication, transcription, translation, and repair are intact, but catabolic and biosynthetic activities are minimized. The number of identifiable transporters is small, and no phosphoenolpyruvate:phosphotransferase carbohydrate transporters were found. Potential virulence factors include a family of 12 potential membrane proteins and several putative hemolysins. Comparison of the T. pallidum genome sequence with that of another pathogenic spirochete, Borrelia burgdorferi, the agent of Lyme disease, identified unique and common genes and substantiates the considerable diversity observed among pathogenic spirochetes.
Assuntos
Genoma Bacteriano , Análise de Sequência de DNA , Treponema pallidum/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Grupo Borrelia Burgdorferi/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Reparo do DNA/genética , Replicação do DNA/genética , Enzimas de Restrição do DNA/genética , Metabolismo Energético/genética , Genes Bacterianos , Genes Reguladores , Resposta ao Choque Térmico/genética , Lipoproteínas/genética , Proteínas de Membrana/genética , Dados de Sequência Molecular , Movimento , Fases de Leitura Aberta , Consumo de Oxigênio/genética , Biossíntese de Proteínas , Recombinação Genética , Origem de Replicação , Transcrição Gênica , Treponema pallidum/metabolismo , Treponema pallidum/patogenicidadeRESUMO
Chromosome 2 of Plasmodium falciparum was sequenced; this sequence contains 947,103 base pairs and encodes 210 predicted genes. In comparison with the Saccharomyces cerevisiae genome, chromosome 2 has a lower gene density, introns are more frequent, and proteins are markedly enriched in nonglobular domains. A family of surface proteins, rifins, that may play a role in antigenic variation was identified. The complete sequencing of chromosome 2 has shown that sequencing of the A+T-rich P. falciparum genome is technically feasible.
Assuntos
Cromossomos/genética , Genes de Protozoários , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Análise de Sequência de DNA , Sequência de Aminoácidos , Animais , Antígenos de Protozoários/química , Antígenos de Protozoários/genética , Composição de Bases , Evolução Molecular , Genoma de Protozoário , Íntrons , Proteínas de Membrana/química , Proteínas de Membrana/genética , Dados de Sequência Molecular , Família Multigênica , Mapeamento Físico do Cromossomo , Proteínas de Protozoários/química , RNA de Protozoário/genética , RNA de Transferência de Ácido Glutâmico/genética , Sequências Repetitivas de Ácido Nucleico , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de SequênciaRESUMO
The complete nucleotide sequence (580,070 base pairs) of the Mycoplasma genitalium genome, the smallest known genome of any free-living organism, has been determined by whole-genome random sequencing and assembly. A total of only 470 predicted coding regions were identified that include genes required for DNA replication, transcription and translation, DNA repair, cellular transport, and energy metabolism. Comparison of this genome to that of Haemophilus influenzae suggests that differences in genome content are reflected as profound differences in physiology and metabolic capacity between these two organisms.
Assuntos
Genoma Bacteriano , Mycoplasma/genética , Análise de Sequência de DNA , Variação Antigênica/genética , Proteínas de Bactérias/genética , Transporte Biológico/genética , Reparo do DNA/genética , Replicação do DNA/genética , DNA Bacteriano/genética , Bases de Dados Factuais , Metabolismo Energético/genética , Genes Bacterianos , Haemophilus influenzae/genética , Dados de Sequência Molecular , Mycoplasma/imunologia , Mycoplasma/metabolismo , Fases de Leitura Aberta , Biossíntese de Proteínas , Transcrição GênicaRESUMO
Neisseria meningitidis is a major cause of bacterial septicemia and meningitis. Sequence variation of surface-exposed proteins and cross-reactivity of the serogroup B capsular polysaccharide with human tissues have hampered efforts to develop a successful vaccine. To overcome these obstacles, the entire genome sequence of a virulent serogroup B strain (MC58) was used to identify vaccine candidates. A total of 350 candidate antigens were expressed in Escherichia coli, purified, and used to immunize mice. The sera allowed the identification of proteins that are surface exposed, that are conserved in sequence across a range of strains, and that induce a bactericidal antibody response, a property known to correlate with vaccine efficacy in humans.
Assuntos
Antígenos de Bactérias/imunologia , Proteínas de Bactérias/imunologia , Vacinas Bacterianas , Genoma Bacteriano , Neisseria meningitidis/genética , Neisseria meningitidis/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/química , Antígenos de Bactérias/genética , Antígenos de Superfície/química , Antígenos de Superfície/genética , Antígenos de Superfície/imunologia , Cápsulas Bacterianas , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Vacinas Bacterianas/genética , Vacinas Bacterianas/imunologia , Sequência Conservada , Escherichia coli/genética , Humanos , Soros Imunes/imunologia , Camundongos , Neisseria meningitidis/classificação , Neisseria meningitidis/patogenicidade , Fases de Leitura Aberta , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/isolamento & purificação , Recombinação Genética , Análise de Sequência de DNA , Sorotipagem , Vacinação , VirulênciaRESUMO
We report on the quality of a whole-genome assembly of Drosophila melanogaster and the nature of the computer algorithms that accomplished it. Three independent external data sources essentially agree with and support the assembly's sequence and ordering of contigs across the euchromatic portion of the genome. In addition, there are isolated contigs that we believe represent nonrepetitive pockets within the heterochromatin of the centromeres. Comparison with a previously sequenced 2.9- megabase region indicates that sequencing accuracy within nonrepetitive segments is greater than 99. 99% without manual curation. As such, this initial reconstruction of the Drosophila sequence should be of substantial value to the scientific community.
Assuntos
Biologia Computacional , Drosophila melanogaster/genética , Genoma , Análise de Sequência de DNA , Algoritmos , Animais , Cromatina/genética , Mapeamento de Sequências Contíguas , Eucromatina , Genes de Insetos , Heterocromatina/genética , Dados de Sequência Molecular , Mapeamento Físico do Cromossomo , Sequências Repetitivas de Ácido Nucleico , Sitios de Sequências RotuladasRESUMO
A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.
Assuntos
Genoma Humano , Projeto Genoma Humano , Análise de Sequência de DNA , Algoritmos , Animais , Bandeamento Cromossômico , Mapeamento Cromossômico , Cromossomos Artificiais Bacterianos , Biologia Computacional , Sequência Consenso , Ilhas de CpG , DNA Intergênico , Bases de Dados Factuais , Evolução Molecular , Éxons , Feminino , Duplicação Gênica , Genes , Variação Genética , Humanos , Íntrons , Masculino , Fenótipo , Mapeamento Físico do Cromossomo , Polimorfismo de Nucleotídeo Único , Proteínas/genética , Proteínas/fisiologia , Pseudogenes , Sequências Repetitivas de Ácido Nucleico , Retroelementos , Análise de Sequência de DNA/métodos , Especificidade da EspécieRESUMO
The 2,272,351-base pair genome of Neisseria meningitidis strain MC58 (serogroup B), a causative agent of meningitis and septicemia, contains 2158 predicted coding regions, 1158 (53.7%) of which were assigned a biological role. Three major islands of horizontal DNA transfer were identified; two of these contain genes encoding proteins involved in pathogenicity, and the third island contains coding sequences only for hypothetical proteins. Insights into the commensal and virulence behavior of N. meningitidis can be gleaned from the genome, in which sequences for structural proteins of the pilus are clustered and several coding regions unique to serogroup B capsular polysaccharide synthesis can be identified. Finally, N. meningitidis contains more genes that undergo phase variation than any pathogen studied to date, a mechanism that controls their expression and contributes to the evasion of the host immune system.
Assuntos
Genoma Bacteriano , Neisseria meningitidis/genética , Neisseria meningitidis/patogenicidade , Análise de Sequência de DNA , Variação Antigênica , Antígenos de Bactérias/imunologia , Bacteriemia/microbiologia , Cápsulas Bacterianas/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/fisiologia , Elementos de DNA Transponíveis , Evolução Molecular , Fímbrias Bacterianas/genética , Humanos , Meningite Meningocócica/microbiologia , Infecções Meningocócicas/microbiologia , Dados de Sequência Molecular , Mutação , Neisseria meningitidis/classificação , Neisseria meningitidis/fisiologia , Fases de Leitura Aberta , Óperon , Filogenia , Recombinação Genética , Sorotipagem , Transformação Bacteriana , Virulência/genéticaRESUMO
The 2,160,837-base pair genome sequence of an isolate of Streptococcus pneumoniae, a Gram-positive pathogen that causes pneumonia, bacteremia, meningitis, and otitis media, contains 2236 predicted coding regions; of these, 1440 (64%) were assigned a biological role. Approximately 5% of the genome is composed of insertion sequences that may contribute to genome rearrangements through uptake of foreign DNA. Extracellular enzyme systems for the metabolism of polysaccharides and hexosamines provide a substantial source of carbon and nitrogen for S. pneumoniae and also damage host tissues and facilitate colonization. A motif identified within the signal peptide of proteins is potentially involved in targeting these proteins to the cell surface of low-guanine/cytosine (GC) Gram-positive species. Several surface-exposed proteins that may serve as potential vaccine candidates were identified. Comparative genome hybridization with DNA arrays revealed strain differences in S. pneumoniae that could contribute to differences in virulence and antigenicity.
Assuntos
Genoma Bacteriano , Análise de Sequência de DNA , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/patogenicidade , Antígenos de Bactérias , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Vacinas Bacterianas , Composição de Bases , Metabolismo dos Carboidratos , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Cromossomos Bacterianos/genética , Biologia Computacional , Elementos de DNA Transponíveis , DNA Bacteriano/química , DNA Bacteriano/genética , Duplicação Gênica , Genes Bacterianos , Hexosaminas/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Recombinação Genética , Sequências Repetitivas de Ácido Nucleico , Especificidade da Espécie , Streptococcus pneumoniae/imunologia , Streptococcus pneumoniae/metabolismo , Virulência , Óperon de RNArRESUMO
The complete genome sequence of the radiation-resistant bacterium Deinococcus radiodurans R1 is composed of two chromosomes (2,648,638 and 412,348 base pairs), a megaplasmid (177,466 base pairs), and a small plasmid (45,704 base pairs), yielding a total genome of 3,284, 156 base pairs. Multiple components distributed on the chromosomes and megaplasmid that contribute to the ability of D. radiodurans to survive under conditions of starvation, oxidative stress, and high amounts of DNA damage were identified. Deinococcus radiodurans represents an organism in which all systems for DNA repair, DNA damage export, desiccation and starvation recovery, and genetic redundancy are present in one cell.
Assuntos
Genoma Bacteriano , Cocos Gram-Positivos/genética , Mapeamento Físico do Cromossomo , Análise de Sequência de DNA , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Catalase/genética , Cromossomos Bacterianos/genética , Dano ao DNA , Reparo do DNA/genética , DNA Bacteriano/genética , Metabolismo Energético , Genes Bacterianos , Cocos Gram-Positivos/química , Cocos Gram-Positivos/classificação , Cocos Gram-Positivos/efeitos da radiação , Dados de Sequência Molecular , Fases de Leitura Aberta , Estresse Oxidativo , Plasmídeos , Tolerância a Radiação , Sequências Repetitivas de Ácido Nucleico , Superóxido Dismutase/genética , Thermus/química , Thermus/genética , Raios UltravioletaRESUMO
A cDNA for a member of the G protein-coupled receptor family was isolated from Drosophila using a probe derived from a human beta 2-adrenergic receptor cDNA. This Drosophila receptor gene is localized at 99A10-B1 on the right arm of chromosome 3 and is preferentially expressed in Drosophila heads. The insect octopamine receptor has been permanently expressed in mammalian cells, where it mediates the attenuation of adenylate cyclase activity and exhibits a pharmacological profile consistent with an octopamine type 1 receptor. Sequence and pharmacological comparisons indicate that the octopamine receptor is unique but closely related to mammalian adrenergic receptors, perhaps as an evolutionary precursor.