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PubMed2004

Targeted mutagenesis of the farnesylation site of Drosophila Ggammae disrupts membrane association of the G protein betagamma complex and affects the light sensitivity of the visual system.

Activation of phototransduction in the compound eye of Drosophila is mediated by a heterotrimeric G protein that couples to the effector enzyme phospholipase Cbeta. The gamma subunit of this G protein (Ggammae) as well as gamma subunits of vertebrate transducins contain a carboxyl-terminal CAAX motif (C, cysteine; A, aliphatic amino acid; X, any amino acid) with a consensus sequence for protein farnesylation. To examine the function of Ggammae farnesylation, we mutated the farnesylation site and overexpressed the mutated Ggammae in Drosophila. Mass spectrometry of overexpressed Ggammae subunits revealed that nonmutated Ggammae is modified by farnesylation, whereas the mutated Ggammae is not farnesylated. In the transgenic flies, mutated Ggammae forms a dimeric complex with Gbetae, with the consequence that the fraction of non-membrane-bound Gbetagamma is increased. Thus, farnesylation of Ggammae facilitates the membrane attachment of the Gbetagamma complex. We also expressed human Ggammarod in Drosophila photoreceptors. Despite similarities in the primary structure between the transducin gamma subunit and Drosophila Ggammae, we observed no interaction of human Ggammarod with Drosophila Gbetae. This finding indicates that human Ggammarod and Drosophila Ggammae provide different interfaces for the interaction with Gbeta subunits. Electroretinogram recordings revealed a significant loss of light sensitivity in eyes of transgenic flies that express mutated Ggammae. This loss in light sensitivity reveals that post-translational farnesylation is a critical step for the formation of membrane-associated Galphabetagamma required for transmitting light activation from rhodopsin to phospholipase Cbeta.

Amino Acid Motifs↗
PubMed1987

Drosophila laminin: characterization and localization.

Drosophila laminin was isolated from the medium of Drosophila Kc cell cultures. It was purified by velocity sedimentation, gel filtration, and chromatography. Drosophila laminin is a disulfide-linked molecule consisting of three chains with apparent molecular masses of 400, 215, and 185 kD. In electron micrographs, it has the cross-shaped appearance with globular domains characteristic of vertebrate laminin with closely similar dimensions. The amino acid composition and lectin-binding properties of Drosophila laminin are given. Polyclonal antibodies to Drosophila laminin were prepared and their specificity was established. In developing embryos immunofluorescence staining was detected between 6 and 8 h of development; and in sections of 8-9-h and older embryos immunostaining was seen at sites where basement membranes are present surrounding internal organs, muscles, underlying the hypodermal epithelium, and in the nervous system. Basement membrane staining was also seen in larva and adults. Cells from Drosophila embryos dissociated at the cellular blastoderm stage were grown in culture and some specific, differentiated cells synthesized laminin after several hours of culture as shown by immunofluorescence. The significance of the evolutionary conservation of the structure of this basement membrane component is discussed.

Amino Acids↗
PubMed1992

Analysis of Drosophila paramyosin: identification of a novel isoform which is restricted to a subset of adult muscles.

In this report we show that Drosophila melanogaster muscles contain the standard form of the thick filament protein paramyosin, as well as a novel paramyosin isoform, which we call miniparamyosin. We have isolated Drosophila paramyosin using previously established methods. This protein is approximately 105 kD and cross-reacts with polyclonal antibodies made against Caenorhabditis elegans or Heliocopris dilloni paramyosin. The Heliocopris antibody also cross-reacts with a approximately 55-kD protein which may be miniparamyosin. We have cloned and sequenced cDNA's encoding both Drosophila isoforms. Standard paramyosin has short nonhelical regions at each terminus flanking the expected alpha-helical heptad repeat seen in other paramyosins and in myosin heavy chains. The COOH-terminal 363 amino acids are identical in standard and miniparamyosin. However, the smaller isoform has 114 residues at the NH2 terminus that are unique as compared to the current protein sequence data base. The paramyosin gene is located at chromosome position 66E1. It appears to use two promoters to generate mRNA's that have either of two different 5' coding sequences joined to common 3' exons. Each protein isoform is encoded by two transcripts that differ only in the usage of polyadenylation signals. This results in four size classes of paramyosin mRNA which are expressed in a developmentally regulated pattern consistent with that observed for other muscle-specific RNA's in Drosophila. In situ hybridization to Drosophila tissue sections shows that standard paramyosin is expressed in all larval and adult muscle tissues whereas miniparamyosin is restricted to a subset of the adult musculature. Thus miniparamyosin is a novel muscle-specific protein that likely plays a role in thick filament structure or function in some adult muscles of Drosophila.

Amino Acid Sequence↗
PubMed1992

Molecular cloning and developmental expression of the catalytic and 65-kDa regulatory subunits of protein phosphatase 2A in Drosophila.

cDNA clones encoding the catalytic subunit and the 65-kDa regulatory subunit of protein phosphatase 2A (PR65) from Drosophila melanogaster have been isolated by homology screening with the corresponding human cDNAs. The Drosophila clones were used to analyze the spatial and temporal expression of the transcripts encoding these two proteins. The Drosophila PR65 cDNA clones contained an open reading frame of 1773 nucleotides encoding a protein of 65.5 kDa. The predicted amino acid sequence showed 75 and 71% identity to the human PR65 alpha and beta isoforms, respectively. As previously reported for the mammalian PR65 isoforms, Drosophila PR65 is composed of 15 imperfect repeating units of approximately 39 amino acids. The residues contributing to this repeat structure show also the highest sequence conservation between species, indicating a functional importance for these repeats. The gene encoding Drosophila PR65 was located at 29B1,2 on the second chromosome. A major transcript of 2.8 kilobase (kb) encoding the PR65 subunit and two transcripts of 1.6 and 2.5 kb encoding the catalytic subunit could be detected throughout Drosophila development. All of these mRNAs were most abundant during early embryogenesis and were expressed at lower levels in larvae and adult flies. In situ hybridization of different developmental stages showed a colocalization of the PR65 and catalytic subunit transcripts. The mRNA expression is high in the nurse cells and oocytes, consistent with a high equally distributed expression in early embryos. In later embryonal development, the expression remains high in the nervous system and the gonads but the overall transcript levels decrease. In third instar larvae, high levels of mRNA could be observed in brain, imaginal discs, and in salivary glands. These results indicate that protein phosphatase 2A transcript levels change during development in a tissue and in a time-specific manner.

Amino Acid Sequence↗
PubMed1980

Evidence for a complex class of nonadenylated mRNA in Drosophila.

The amount, by mass, of poly(A+) mRNA present in the polyribosomes of third-instar larvae of Drosophila melanogaster, and the relative contribution of the poly(A+) mRNA to the sequence complexity of total polysomal RNA, has been determined. Selective removal of poly(A+) mRNA from total polysomal RNA by use of either oligo-dT-cellulose, or poly(U)-sepharose affinity chromatography, revealed that only 0.15% of the mass of the polysomal RNA was present as poly(A+) mRNA. The present study shows that this RNA hybridized at saturation with 3.3% of the single-copy DNA in the Drosophila genome. After correction for asymmetric transcription and reactability of the DNA, 7.4% of the single-copy DNA in the Drosophila genome is represented in larval poly(A+) mRNA. This corresponds to 6.73 X 10(6) nucleotides of mRNA coding sequences, or approximately 5,384 diverse RNA sequences of average size 1,250 nucleotides. However, total polysomal RNA hybridizes at saturation to 10.9% of the single-copy DNA sequences. After correcting this value for asymmetric transcription and tracer DNA reactability, 24% of the single-copy DNA in Drosophila is represented in total polysomal RNA. This corresponds to 2.18 X 10(7) nucleotides of RNA coding sequences or 17,440 diverse RNA molecules of size 1,250 nucleotides. This value is 3.2 times greater than that boserved for poly(A+) mRNA, and indicates that congruent to 69% of the polysomal RNA sequence complexity is contributed by nonadenylated RNA. Futhermore, if the number of different structural genes represented in total polysomal RNA is congruent to 1.7 X 10(4), then the number of genes expressed in third-instar larvae exceeds the number of chromomeres in Drosophila by about a factor of three. This numbeology indicates that the number of chromomeres observed in polytene chromosomes does not reflect the number of structural gene sequences in the Drosophila genome.

Animals↗
PubMed2000

Function and structure of Drosophila glycans.

Through the application of classic organismal genetic strategies, such as mutagenesis and interaction screens, Drosophila melanogaster provides opportunities to understand glycan function. For instance, screens for Drosophila genes that establish dorsal-ventral polarity in the embryo or that influence cellular differentiation through signal modulation have identified putative glycan modifying enzymes. Other genetic and molecular approaches have demonstrated the existence of phylogenetically conserved and novel oligosaccharide processing activities and carbohydrate binding proteins. While the structural characterization of Drosophila oligosaccharide diversity has lagged behind the elucidation of glycan function, landmarks are becoming apparent in the carbohydrate terrain. For instance, O-linked GlcNAc and mucins, spatially and temporally regulated N-linked oligosaccharide expression, glycosphingolipids, heparan sulfate, chondroitin sulfate and polysialic acid have all been described. A major challenge for Drosophila glycobiology is to expand the oligosaccharide structural database while endeavoring to link glycan characterization to functional analysis. The completion of the Drosophila genome sequencing project will yield a broad portfolio of glycosyltransferases, glycan modifying enzymes and lectins requiring characterization. To this end, the great range of genetic tools that allow the controlled spatial and temporal expression of transgenes in Drosophila will permit unprecedented manipulation of glycosylation in a whole organism.

Animals↗
PubMed1987

Evaluation of potential mammalian genotoxins using Drosophila: the need for a change in test strategy.

Recent developments in the field of genetic toxicology testing, in particular the outcome of several international collaborative studies, necessitate a re-appraisal of the potential use of Drosophila assays for mutagen testing. For an evaluation of the test performance of the classical sex-linked recessive lethal (SLRL) assay to detect as mutagens mammalian carcinogens, the parameters sensitivity, specificity and accuracy were compared, using as a database the Gene-Tox Report and the results of two international collaborative studies (CSSTT and IPCS). A characteristic of the assay's performance is its low sensitivity (0.33-0.79) and low accuracy (0.50-0.73), when genotoxins other than direct-acting agents and simple promutagens (single-step activation) were included in the analysis. However, the high specificity (0.86-1.0) of the SLRL assay means that in general a positive result has considerable value for prediction of potential genotoxicity in mammals. Experience in the field of carcinogenesis dictates that organ specificity in one species cannot be predicted on the basis of observations in another. It is concluded here that any attempt to use Drosophila assays on the basis of just exposure dose as predictors of effects likely to occur in specific organs in mammals will fail. Examples are provided by the procarcinogens diethylnitrosamine (DEN), vinyl chloride (VC) and hexamethylphosphoramide (HMPA), as well as by the direct-acting mutagens diethylsulphate (DES), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and hycanthone. This view is that it would be highly desirable to compare the Drosophila results on germ cells with in vivo mammalian germ-line tests on the basis of molecular dosimetry studies as proposed by Lee. This approach then should enable the comparison on an adequate basis of mechanism of mutagenesis in Drosophila and rodents. It is specifically concluded that the potential value of the SLRL and any other Drosophila germ-cell assay should be judged against their capability of predicting mammalian genotoxicity in a broad sense but certainly not in specific organs. In this function, germ-line assays will have to compete with the novel tests measuring somatic mutation/mitotic recombination (SMART) in Drosophila. The values obtained for sensitivity (0.75-0.78) and accuracy (0.83-0.86) for the latter tests were clearly better than those found for the SLRL test, suggesting that SMART assays present a promising new development. However, the final judgement of their probable role as complementary or confirmatory methods of genotoxic activity observed in Salmonella must await the outcome of the evaluation studies in progress in several laboratories.

Animals↗
PubMed1991

Polypeptide components of Drosophila small nuclear ribonucleoprotein particles.

In eukaryotes splicing of pre-mRNAs is mediated by the spliceosome, a dynamic complex of small nuclear ribonucleoprotein particles (snRNPs) that associate transiently during spliceosome assembly and the splicing reaction. We have purified snRNPs from nuclear extracts of Drosophila cells by affinity chromatography with an antibody specific for the trimethylguanosine (m3G) cap structure of snRNAs U1-U5. The polypeptide components of Drosophila snRNPs have been characterized and shown to consist of a number of proteins shared by all the snRNPs, and some proteins which appear to be specific to individual snRNP particles. On the basis of their apparent molecular weight and antigenicity many of these common and particle specific Drosophila snRNP proteins are remarkably conserved between Drosophila and human spliceosomes. By probing western blots of the Drosophila snRNP polypeptides with a number of antisera raised against human snRNP proteins, Drosophila polypeptides equivalent to many of the HeLa snRNP-common proteins have been identified, as well as candidates for a number of U1, U2 and U5-specific proteins.

Animals↗
PubMed1992

Isolation and characterization of a gene encoding DNA topoisomerase I in Drosophila melanogaster.

We synthesized a DNA probe specific for the gene encoding eucaryotic DNA topoisomerase I by the polymerase chain reaction. The sequences of the primers for this reaction were deduced from the regions with extensive homology among the enzymes from the fission and budding yeasts, and the human. From the clones isolated by screening a Drosophila cDNA library with this DNA probe, two cDNA clones of 3.8 and 5.2 kb were characterized and completely sequenced. Both cDNA sequences contain an identical open reading frame for 972 amino acid residues. The 3.8 kb messenger RNA is likely generated by using a polyadenylation site 5' upstream to that used in generating the 5.2 kb mRNA. The predicted amino acid sequence shows that a segment of 420 amino acid residues at the amino terminus is hydrophilic, similar to the amino terminal 200 residues in the yeast and human enzymes. Furthermore, the Drosophila enzyme is unique in that the amino terminal 200 residues are enriched in serine and histidine residues; most of them are present in clusters. The rest of the Drosophila sequence is highly homologous to those from yeast and human enzymes. The evolutionarily conserved residues are identified and are likely the critical elements for the structure and function of this enzyme. A plasmid vector containing the cloned cDNA was constructed for the expression of Drosophila protein in Escherichia coli. The enzymatic and immunochemical analysis of the polypeptide produced in this heterologous expression system demonstrated that the expressed protein shares similar enzymatic properties and antigenic epitopes with DNA topoisomerase I purified from Drosophila embryos or tissue culture cells, thus establishing the bacterial expression system being useful for the future structure/function analysis of the Drosophila enzyme.

Amino Acid Sequence↗
PubMed1999

The FlyBase database of the Drosophila Genome Projects and community literature.

The FlyBase Drosophila genetics database and the public interfaces of the Berkeley Drosophila Genome Project (BDGP) and European Drosophila Genome Project (EDGP) are in the process of integrating. At present, the data of these projects are available from independent, but hyperlinked, WWW sites (FlyBase URL, http://flybase. bio.indiana.edu/; BDGP URL, http://fruitfly.berkeley.edu/; EDGP URL, http://edgp.ebi.ac.uk/ ). Because of the considerable overlap of data classes between the contributions of the Drosophila genome projects and the Drosophila community, the new and enlarged FlyBase consortium views the implementation of a single integrated Drosophila genomics/genetics server as essential to the scientific community. This integration will occur in a stepwise fashion over the next 1-2 years. In this report, the salient features of the current databases and how to interrogate and navigate the extensive data sets are discussed.

Animals↗
PubMed2006

Identification of multiple transcription initiation, polyadenylation, and splice sites in the Drosophila melanogaster TART family of telomeric retrotransposons.

The Drosophila non-long terminal repeat (non-LTR) retrotransposons TART and HeT-A specifically retrotranspose to chromosome ends to maintain Drosophila telomeric DNA. Relatively little is known, though, about the regulation of their expression and their retrotransposition to telomeres. We have used rapid amplification of cDNA ends (RACE) to identify multiple transcription initiation and polyadenylation sites for sense and antisense transcripts of three subfamilies of TART elements in Drosophila melanogaster. These results are consistent with the production of an array of TART transcripts. In contrast to other Drosophila non-LTR elements, a major initiation site for sense transcripts was mapped near the 3' end of the TART 5'-untranslated region (5'-UTR), rather than at the start of the 5'-UTR. A sequence overlapping this sense start site contains a good match to an initiator consensus for the transcription start sites of Drosophila LTR retrotransposons. Interestingly, analysis of 5' RACE products for antisense transcripts and the GenBank EST database revealed that TART antisense transcripts contain multiple introns. Our results highlight differences between transcription of TART and of other Drosophila non-LTR elements and they provide a foundation for testing the relationship between exceptional aspects of TART transcription and TART's specialized role at telomeres.

5' Untranslated Regions↗
PubMed2001

Local changes in GC/AT substitution biases and in crossover frequencies on Drosophila chromosomes.

I present here evidence of remarkable local changes in GC/AT substitution biases and in crossover frequencies on Drosophila chromosomes. The substitution pattern at 10 loci in the telomeric region of the X chromosome was studied for four species of the Drosophila melanogaster species subgroup. Drosophila orena and Drosophila erecta are clearly the most closely related species pair (the erecta complex) among the four species studied; however, the overall data at the 10 loci revealed a clear dichotomy in the silent substitution patterns between the AT-biased- substitution melanogaster and erecta lineages and the GC-biased-substitution yakuba and orena lineages, suggesting two or more independent changes in GC/AT substitution biases. More importantly, the results indicated a between- loci heterogeneity in GC/AT substitution bias in this small region independently in the yakuba and orena lineages. Indeed, silent substitutions in the orena lineage were significantly biased toward G and C at the consecutive yellow, lethal of scute, and asense loci, but they were significantly biased toward A and T at sta. The substitution bias toward G and C was centered in different areas in yakuba (significantly biased at EG:165H7.3, EG:171D11.2, and suppressor of sable). The similar silent substitution patterns in coding and noncoding regions, furthermore, suggested mutational biases as a cause of the substitution biases. On the other hand, previous study reveals that Drosophila yakuba has about 20-fold higher crossover frequencies in the telomeric region of the X chromosome than does D. melanogaster; this study revealed that the total genetic map length of the yakuba X chromosome was only about 1.5 times as large as that of melanogaster and that the map length of the X-telomeric y-sta region did not differ between Drosophila yakuba and D. erecta. Taken together, the data strongly suggested that an approximately 20- fold reduction in the X-telomeric crossover frequencies occurred in the ancestral population of D. melanogaster after the melanogaster-yakuba divergence but before the melanogaster-simulans divergence.

Animals↗
PubMed1991

The molecular evolution of the alcohol dehydrogenase locus and the phylogeny of Hawaiian Drosophila.

DNA sequences in the alcohol dehydrogenase genes of flies representing the major groups of Hawaiian Drosophila are used to clarify the relationships of these groups, among themselves and with mainland Drosophila. The topology of the tree derived from these sequences agrees with karyotypic and morphological data but disagrees, in part, with the results of an earlier study that used immunological comparisons between variants of a larval hemolymph protein. A time scale, derived from a comparison of closely related Hawaiian Drosophila species, provides divergence-time estimates that are substantially more recent than those obtained from the immunological studies, although they are still within the bounds set by fossil and biogeographical evidence. The two major lineages of Hawaiian Drosophila, the scaptomyzoids and the drosophiloids, are shown to be widely separated from one another. The scaptomyzoids appear to have diverged early in the history of the subgenus Drosophila, greater than 25 Mya. While hundreds of scaptomyzoid species are found in the Hawaiian archipelago, many fewer are found elsewhere around the world, suggesting that they could have originated outside Hawaii. The drosophiloid lineage is strictly endemic to Hawaii and originated little more than 10 Mya, according to the alcohol dehydrogenase molecular clock. Thus, Drosophila apparently inhabited the Hawaiian archipelago (greater than or equal to 5 Myr before the emergence of the oldest existing high island, Kauai, 5 Mya.

Alcohol Dehydrogenase↗
PubMed1991

A novel cyclin gene from Drosophila complements CLN function in yeast.

In the yeast Saccharomyces cerevisiae three G1-S cyclins, or CLNs, have been identified that trigger the G1-S transition of the cell cycle. The regulation of the G1-S transition is particularly intriguing in Drosophila both because G1 is added to the cell cycle developmentally and G1-S regulators may drive the polytene cell cycle. To identify potential G1-S regulators from Drosophila, a cDNA expression library was constructed in which Kc cell cDNAs were placed in a high-copy S. cerevisiae vector under the control of the constitutive ADH1 promoter. Following transformation into an S. cerevisiae strain lacking all three CLN gene products, we identified one Drosophila cDNA that complemented the yeast G1 cyclins and restored growth to near wild-type levels. The CLNDm gene is present as a single copy in the Drosophila genome and encodes a 1.2-kb mRNA. DNA sequence analysis reveals that although this gene has cyclin homology, it is a new member of the cyclin gene family. CLNDm mRNA expression correlates with periods of maximal cell division throughout Drosophila development. The transcript is most abundant in early embryos, and it is present in low levels in larvae, pupae, and adults. Drosophila embryos hybridized in situ to this cyclin gene show uniform expression of the message throughout the embryo, with diminishing expression as embryogenesis proceeds.

Amino Acid Sequence↗
PubMed1975

RNA polymerase B from Drosophila melanogaster larvae. Purification and partial characterization.

A purification procedure is described by which we obtained DNA-dependent RNA polymerase B (or II) from third-instar larvae of Drosophila melanogaster in essentially pure form. The enzyme is similar to the analogous polymerases from other eukaryotes in its enzymic and structural properties. It preferentially transcribes DNAs containing single-stranded regions, and it is inhibited by low amounts of the toxin alpha-amanitin; 50% inhibition occurs at an alpha-amanitin concentration of 0.03 mug/ml. Dodecylsulfate-polyacrylamide gel electrophoresis resolves the purified Drosophila polymerase B into ten polypeptides with molecular weights as follows: 1 (174000), 2 (137000), 3 (34000), 4 (22000), 5 (18000), 6 and 7 (16000), 8 (15000), and 9 and 10 (less than 15000). The relative amounts of polypeptides 1-4 were constant at molar ratios of approximately 1:1:1:2 in different preparations of the enzyme, while the amounts of polypeptides 5-10 showed more variation. An antiserum directed against the Drosophila RNA polymerase B inhibited the activity in vitro of the B enzymes from Drosophila, yeast, and calf thymus. However, only the Drosophila enzyme gave a precipitin reaction with the antiserum. When the antiserum was added to Drosophila RNA polymerase B at different stages of the purification, the resulting precipitates were found to contain nearly constant proportions of seven of the ten polypeptides present in the purified enzyme.

Amanitins↗
PubMed1990

Drosophila GABAergic systems: sequence and expression of glutamic acid decarboxylase.

A mammalian glutamic acid decarboxylase (GAD) cDNA probe has been utilized to isolate Drosophila cDNA clones that represent a genomic locus in chromosome region 64A. Deletion analysis indicates that this chromosomal locus encodes an enzymatically active GAD protein. The in vitro translation of cRNA representing a Drosophila cDNA clone yields a 57-kDa protein that can be immunoprecipitated by an anti-GAD antiserum. A GAD-immunoreactive protein of the same size can also be detected in Drosophila head extracts. The nucleotide sequence derived from two overlapping Drosophila cDNA clones predicts a 57,759-dalton protein composed of 510 residues that is 53% identical to mammalian GAD. Sequence comparisons of mammalian and Drosophila GAD identify two highly conserved regions (greater than or equal to 70% identity), one of which encompasses a putative co-factor-binding domain. Transcriptional analyses show that expression of the Drosophila Gad gene commences early in embryonic development (4-8 h) and continues in all later developmental stages. A 3.1-kb class of mRNA is detected throughout embryogenesis, in all three larval stages, in pupae, and in adults. This transcript class has a widespread distribution in the adult CNS. A smaller 2.6-kb transcript is expressed in a developmentally regulated manner; it is detected only in embryos and pupae.

Amino Acid Sequence↗
PubMed1988

Hawaiian courtship songs: evolutionary innovation in communication signals of Drosophila.

In Hawaii, flies of the genus Drosophila have undergone spectacular adaptive radiation, resulting in the evolution of more than 500 species of Drosophila that are found nowhere else on earth. This taxonomic uniqueness is reflected in behavior and morphology. Hawaiian Drosophila sing songs, as do continental Drosophila; however, the Hawaiian songs have diverged strongly in form and mechanism of production. The click-song of D. fasciculisetae's (Maui) has a carrier frequency an order of magnitude higher than those reported in familiar continental species, such as D. melanogaster (170 hertz). Drosophila fasciculisetae's song resembles a cicada's more than a fly's song. The song of D. cyrtoloma (Maui) has a complex pulse rhythm more typical of crickets than flies. The pulse song of D. silvestris (Hawaii) closely resembles that of D. melanogaster in both pulse rhythm and carrier frequency, but D. melanogaster sings by vibrating its wings, whereas D. silvestris sings through abdominal vibrations. These mechanisms are radical departures from the continental wing song mechanism and are further examples of the remarkable behavioral innovation that has occurred in the Drosophila of Hawaii during their evolutionary transit through these islands.

Animal Communication↗
PubMed1982

Saccharomyces cerevisiae contains a complex multigene family related to the major heat shock-inducible gene of Drosophila.

Saccharomyces cerevisiae contains a family of genes related to the major heat shock-induced gene of Drosophila (hsp 70). Two members of the multigene family (YG100 and YG101) were isolated. The primary DNA sequences of more than one-half of the protein-encoding regions of YG100 and YG101 were determined and compared with the Drosophila hsp 70 gene sequence; the predicted amino acid sequences were 72 and 64% homologous to the sequence of the Drosophila hsp 70 protein, respectively. The predicted amino acid sequences of the yeast genes were 65% homologous. Our results demonstrate a striking sequence conservation of hsp 70-related sequences in evolution. Hybridization of the S. cerevisiae genes to total S. cerevisiae DNA indicated that the multigene family consists of approximately 10 members. Hybridization of labeled RNAs from heat-shocked and control cells suggested that, like transcription of the Drosophila hsp 70 gene, transcription of YG100 or a closely related gene is enhanced after heat shock. However, the amount of RNA sequences homologous to YG101 was reduced after heat shock. A multigene family related to the hsp 70 gene exists in Drosophila; transcription of some members is induced by heat shock, whereas transcription of others is not. Our results suggest that S. cerevisiae, like Drosophila, contains a multigene family of hsp 70-related sequences under complex transcriptional regulation and that the differential control, as well as the nucleotide sequence, has been highly conserved in evolution.

Amino Acid Sequence↗