SEARCH · Search PubMed

Results for “DROSOPHILA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources

PubMed2001

Recombination and the frequency spectrum in Drosophila melanogaster and Drosophila simulans.

Most "tests of neutrality" assess whether particular data sets depart from the predictions of a standard neutral model with no recombination. For Drosophila, where nuclear polymorphism data routinely show evidence of genetic exchange, the assumption of no recombination is often unrealistic. In addition, while conservative, this assumption is made at the cost of a great loss in power. Perhaps as a result, tests of the frequency spectrum based on zero recombination suggest an adequate fit of Drosophila polymorphism data to the predictions of the standard neutral model. Here, we analyze the frequency spectrum of a large number of loci in Drosophila melanogaster and D. simulans using two summary statistics. We use an estimate of the population recombination rate based on a laboratory estimate of the rate of crossing over per physical length and an estimate of the species' effective population size. In contrast to previous studies, we find that roughly half of the loci depart from the predictions of the standard neutral model. The extent of the departure depends on the exact recombination rate, but the global pattern that emerges is robust. Interestingly, these departures from neutral expectations are not unidirectional. The large variance in outcomes may be due to a complex demographic history and inconsistent sampling, or to the pervasive action of natural selection.

Animals↗

PubMed1994

Stable expression of a functional homo-oligomeric Drosophila GABA receptor in a Drosophila cell line.

A cloned Drosophila gamma-aminobutyric acid GABA receptor subunit (Rdl) has been stably expressed as a functional homo-oligomeric ion channel in a Drosophila cell line. Stably-transfected clonal cell lines which expressed high levels of GABA receptor were identified by specific [3H]-muscimol binding. Expression of functional GABA-gated ion channels in these cell lines was demonstrated by electrophysiological recording. Rapid and pronounced rundown of responses to GABA during whole-cell patch clamp recordings was overcome by the inclusion of EGTA in the pipette solution, indicating a possible role for calcium-dependent processes in the functional regulation of this GABA receptor. Relative agonist potencies of the expressed receptor were found to be in the order GABA = TACA > CACA. We have observed a reversible block of the receptor by the convulsant antagonists, picrotoxinin and EBOB, and by the insecticide fipronil. Potentiation of GABA responses was seen with the anaesthetic steroid 5 alpha-pregnan-3 alpha-ol-20-one. No significant effects (either agonist, antagonist or modulatory) were observed with bicuculline (a vertebrate GABAAR antagonist), benzodiazepines or barbiturates (vertebrate GABAAR modulators), or with glycine agonist of the closely related vertebrate glycine receptors). The suitability of this Drosophila stable expression system for the characterization of receptors and ion channels is discussed.

Animals↗

PubMed1984

High-resolution mapping of DNase I-hypersensitive sites of Drosophila heat shock genes in Drosophila melanogaster and Saccharomyces cerevisiae.

High-resolution analysis of the chromatin structure of the promoter regions of five Drosophila heat shock genes showed a similar location for the hypersensitive sequences relative to the start of transcription. For each of the five genes examined--those coding for hsp27, hsp26, hsp23, hsp70, and hsp83--the DNase I-hypersensitive sites in Drosophila melanogaster nuclei mapped to two regions upstream of the coding region. These sites occurred on the average, 115 and 17 base pairs upstream from the start of transcription of the five heat shock genes examined. This latter site corresponded to sequences at or near the TATA consensus sequence. Sites even further upstream of the hsp27, hsp26, and hsp83 genes were also evident. Additionally, for the two genes examined--hsp70 and hsp83--the DNase I-hypersensitive sites were preserved, at least within this level of resolution (+/- 10 base pairs), when the Drosophila genes were integrated into the Saccharomyces cerevisiae genome. This result indicates that the signals responsible for generating these hypersensitive sites are inherent in the DNA sequences and, in this case, are not highly species specific.

Animals↗

PubMed2003

Hybridization and introgression of the genomes of Drosophila nasuta and Drosophila albomicans: evolution of new karyotypes.

Drosophila nasuta (2n = 8) and Drosophila albomicans (2n = 6) are cross-fertile allopatric sibling chromosomal races of the nasuta subgroup of Drosophila. Hybrids of these races can be maintained for any number of generations. Some of the introgressed hybrid lineages of D. nasuta and D. albomicans, after passing through a transient phase of karyotypic polymorphism, ended up with a stable karyotype whose composition is different from those of the parental races. Such hybrid populations were called cytoraces, in which the chromosomes of D. nasuta and D. albomicans are represented in different combinations. The karyotypic composition of 16 such cytoraces have been presented and discussed with reference to evolutionary strategies such as balancing selection, directional selection, and sex-specific effect on different components of the evolving karyotypes.

Animals↗

PubMed1985

The meiotic and mitotic chromosomes of picture-winged Hawaiian Drosophila species. I. Drosophila grimshawi and D. cyrtoloma.

The mitotic and meiotic chromosomes of Drosophila grimshawi and Drosophila cyrtoloma, species of the picture-wing group of Hawaiian Drosophilidae, are described. The "primitive" Drosophila karyotype of five pairs of rods and one pair of dots, found in grimshawi, is compared with the karyotype for cyrtoloma, which consists of five pairs of V-shaped and one pair of J-shaped chromosomes. Cytological material was prepared by an acetoorcein technique and by C-, G-, and N-banding methods. The rod-shaped chromosomes of grimshawi contained approximately 45% heterochromatin as determined by differential staining with Giemsa. Each chromosome of cyrtoloma consists of a euchromatic arm and a heterochromatic arm; the total heterochromatin of the diploid set averaged between 55 and 60%. These measurements approximate the amounts of satellite DNA reported for these two species. Prophase and metaphase figures from both meiotic and mitotic divisions are shown.

Animals↗

PubMed2005

Nuclear-mitochondrial epistasis and drosophila aging: introgression of Drosophila simulans mtDNA modifies longevity in D. melanogaster nuclear backgrounds.

Under the mitochondrial theory of aging, physiological decline with age results from the accumulated cellular damage produced by reactive oxygen species generated during electron transport in the mitochondrion. A large body of literature has documented age-specific declines in mitochondrial function that are consistent with this theory, but relatively few studies have been able to distinguish cause from consequence in the association between mitochondrial function and aging. Since mitochondrial function is jointly encoded by mitochondrial (mtDNA) and nuclear genes, the mitochondrial genetics of aging should be controlled by variation in (1) mtDNA, (2) nuclear genes, or (3) nuclear-mtDNA interactions. The goal of this study was to assess the relative contributions of these factors in causing variation in Drosophila longevity. We compared strains of flies carrying mtDNAs with varying levels of divergence: two strains from Zimbabwe (<20 bp substitutions between mtDNAs), strains from Crete and the United States (approximately 20-40 bp substitutions between mtDNAs), and introgression strains of Drosophila melanogaster carrying mtDNA from Drosophila simulans in a D. melanogaster Oregon-R chromosomal background (>500 silent and 80 amino acid substitutions between these mtDNAs). Longevity was studied in reciprocal cross genotypes between pairs of these strains to test for cytoplasmic (mtDNA) factors affecting aging. The intrapopulation crosses between Zimbabwe strains show no difference in longevity between mtDNAs; the interpopulation crosses between Crete and the United States show subtle but significant differences in longevity; and the interspecific introgression lines showed very significant differences between mtDNAs. However, the genotypes carrying the D. simulans mtDNA were not consistently short-lived, as might be predicted from the disruption of nuclear-mitochondrial coadaptation. Rather, the interspecific mtDNA strains showed a wide range of variation that flanked the longevities seen between intraspecific mtDNAs, resulting in very significant nuclear x mtDNA epistatic interaction effects. These results suggest that even "defective" mtDNA haplotypes could extend longevity in different nuclear allelic backgrounds, which could account for the variable effects attributable to mtDNA haplogroups in human aging.

Amino Acid Substitution↗

PubMed2003

[Heat shock during the development of brain structures of Drosophila: the memory development in the l(1)ts403 mutant of Drosophila melanogaster].

The structures and functions of many genes are homologous in Drosophila and humans. Therefore, studying pathological processes in Drosophila, in particular neurogenerative processes accompanied by progressive memory loss, helps to understand the ethiology of corresponding human disorders and to develop therapeutic strategies. It is believed that the development of neurogenerative diseases might result from alterations in the functioning of the heat shock/chaperone machinery. In view of this, we used Drosophila mutant l(1)ts403 with defective synthesis of heat shock proteins for studying learning and memory in a test of conditioned courtship suppression following a heat shock given at different developmental stages. High learning indices were registered immediately and 30 min after training both in the intact controls and in flies subjected to different developmental heat shocks. This indicated normal learning and memory acquisition in the mutant. At the same time, memory retention (3 h after training) suffered to different extent depending on the developmental stage. The remote effects of heat shock given during the formation of the mushroom bodies indicated the important role of this brain structure in the memory formation. The observed memory defects may result from alterations both in mRNA transport and in the functions of molecular chaperones in the l(1)ts403 mutant.

Animals↗

PubMedDate not supplied

[Effect on the fertility of female Drosophila of sterol metabolism in an ecological-genetic yeast-Drosophila system].

The consequences of sterol deficiency in feeding of adult Drosophila females have been studied. Feeding of Drosophila on nys 1 mutant strain yeast leads to significant increase of non-developed eggs in Drosophila females. The effect of sterol deficiency on oogenesis in virgin and fertilized females has been estimated using different regimens of feeding. Possible mechanisms of arising of fertility defects are discussed.

Animals↗

PubMed1989

Primary structure of the Drosophila laminin B2 chain and comparison with human, mouse, and Drosophila laminin B1 and B2 chains.

Laminin, a major component of basement membranes, is a large glycoprotein consisting of three disulfide-bonded subunits, A, B1, and B2. We have isolated and sequenced a Drosophila laminin B2 chain cDNA clone that spans 5737 nucleotides. The deduced amino acid sequence predicts that the mature and nonglycosylated polypeptide has a chain length of 1606 residues (Mr = 178,665). This B2 chain contains 100 half-cystine residues, most of which are located in two cysteine-rich domains, and 11 N-X-S or N-X-T sequences which are potential sites of N-linked glycosylation. The predicted secondary structure reveals the presence of six structurally distinct domains, of which two are mainly alpha-helical, two are cysteine-rich with homologous repeats, and two are globular regions. The Drosophila B2 chain is 40.3 and 41.1% identical to the human and mouse B2 chains, respectively, and 29.6, 30.0, and 29.4% identical to the Drosophila, human, and mouse B1 chains, respectively.

Amino Acid Sequence↗

PubMed1986

Adaptations of Drosophila and yeasts: their interactions with the volatile 2-propanol in the cactus-microorganism-Drosophila model system.

The interactions of yeasts growing in decaying cactus tissue with and without 2-propanol were studied with respect to the costs and benefits provided to three cactophilic Drosophila species (D. mojavensis, D. arizonensis and D. buzzatii). Two common cactus yeasts, Candida sonorensis and Cryptococcus cereanus, which can tolerate and metabolize 2-propanol, provide benefits to the three Drosophila species in the presence of the alcohol, as compared with another common cactus yeast, Pichia cactophila, which has less tolerance and cannot metabolize 2-propanol. Because 2-propanol is commonly found in decaying cactus tissue and C. sonorensis and Cr. cereanus are also frequently recovered from the rotting tissue being utilized by the Drosophila species, the interactions described here are viewed as a possible adaptation in which the yeast provides benefits to one of its vectors by metabolism of 2-propanol in the habitat.

1-Propanol↗

PubMed1985

[Effect of sterol metabolism in the yeast-Drosophila system on the frequency of radiation-induced aneuploidy in Drosophila melanogaster oocytes].

The influence of sterol metabolism upon mutagenesis in Drosophila melanogaster was investigated using ecological-genetic yeast - drosophila system. Sterol deficiency in the organism of Drosophila was caused by using the strain of Saccharomyces cerevisiae 9-2P712 with a mutation in the nysr1 locus which blocks synthesis of ergosterol as a nutrition substrate for flies. It was concluded that maintenance of females on the mutant yeast strain causes an increase of radiation-induced X-chromosome loss in mature oocytes. Resistance of oocytes to X-ray irradiation is restored, reaching the control level, when 0,1% cholesterol solution in 10% ethanol is added to the yeast biomass. The possible membrane and hormonal mechanisms of elevation of induced aneuploidy and the role of sterol metabolism in ensuring resistance of insects to damaging factors are discussed.

Aneuploidy↗

PubMed1982

The 5- flanking sequences of Drosophila tRNAArg genes control their in vitro transcription in a Drosophila cell extract.

The transcription efficiencies of four Drosophila tRNAArg genes located in a tRNA gene cluster at region 42A on chromosome 2, and containing identical coding sequences, were studied in Drosophila Kc cell extracts. Transcription is modulated by the 5' flanking sequences; efficient transcription is dependent on the presence of an optimal 5' flanking sequence. One of the genes, p17D Arg, is not transcribed in the homologous extract but does compete with the other genes for transcription factors. Deletion of a specific sequence from the 5' flank of the gene of p17D Arg leads to an increase in transcription efficiency. All tRNAArg genes are efficiently transcribed in extracts from HeLa cells. However, introduction of small amounts of Drosophila extract reduces the efficiency of transcription in HeLa extracts. This is due to incompatibility between transcriptional components of the two extracts.

Animals↗

PubMed1993

Drosophila suzukii contains a peptide homologous to the Drosophila melanogaster sex-peptide and functional in both species.

A peptide homologous to the Drosophila melanogaster sex-peptide (SP) was isolated from Drosophila suzukii accessory glands and its amino acid sequence determined. The D. suzukii peptide contains 41 amino acids and has a calculated molecular weight of 5100 Da. Comparison of the sequences reveals strong homologies in the N-terminal and C-terminal parts of the peptides. In the D. suzukii sex-peptide, however, five additional amino acids are inserted after amino acid 7. Based on the sequence of the peptide, a cDNA coding for the D. suzukii peptide was isolated by PCR. Sequence analysis of the cDNA confirmed the SP amino acid sequence determined by peptide sequencing. Furthermore, based on the cDNA sequence, we isolated the D. suzukii sex-peptide gene by inverse PCR. The D. suzukii sex-peptide gene contains an intron and codes for a 60 amino acid precursor. The D. melanogaster and the D. suzuki sex-peptides elicit rejection behaviour in the presence of males and an increased egg laying in virgin females of both species.

Amino Acid Sequence↗

PubMed2002

Penelope retroelements from Drosophila virilis are active after transformation of Drosophila melanogaster.

The Penelope family of retroelements was first described in species of the Drosophila virilis group. Intact elements encode a reverse transcriptase and an endonuclease of the UvrC type, which may play a role in Penelope integration. Penelope is a key element in the induction of D. virilis hybrid dysgenesis, which involves the mobilization of several unrelated families of transposable elements. We here report the successful introduction of Penelope into the germ line of Drosophila melanogaster by P element-mediated transformation with three different constructs. Penelope is actively transcribed in the D. melanogaster genome only in lines transformed with a construct containing a full-length Penelope clone. The transcript is identical to that detected in D. virilis dysgenic hybrids. Most newly transposed Penelope elements have a very complex organization. Significant proliferation of Penelope copy number occurred in some lines during the 24-month period after transformation. The absence of copy number increase with two other constructs suggests that the 5' andor 3' UTRs of Penelope are required for successful transposition in D. melanogaster. No insect retroelement has previously been reported to be actively transcribed and to increase in copy number after interspecific transformation.

Animals↗

PubMed1990

Structural and functional comparisons of the Drosophila virilis and Drosophila melanogaster rough genes.

We have isolated the homeobox gene rough (ro) from Drosophila virilis. Comparison of the predicted amino acid sequences of the D. melanogaster and D. virilis rough proteins reveals that domains of high conservation, including the homeodomain, are interspersed with highly diverged regions. Stretches of significant sequence conservation are also observed in the 5' promoter region and in the introns. The D. virilis rough gene rescues the rough mutant phenotype and is properly regulated when introduced into the D. melanogaster genome. Thus the rough protein as well as the cis-regulatory elements that ensure proper temporal and spatial regulation are functionally conserved between these Drosophila species.

Amino Acid Sequence↗

PubMed1993

The interaction of bride of sevenless with sevenless is conserved between Drosophila virilis and Drosophila melanogaster.

An inductive interaction between the sevenless (sev) transmembrane tyrosine kinase receptor and the bride of sevenless (boss) transmembrane ligand is required for the development of the R7 photoreceptor neuron in the compound eye of Drosophila melanogaster. The boss protein is proposed to contain a large N-terminal extracellular domain, seven transmembrane segments, and a C-terminal cytoplasmic tail. The boss protein from Drosophila virilis (bossvir) retains strong amino acid identity with loss from D. melanogaster (bossmel): 73% identity in the N-terminal extracellular domain and 91% identity in the seven-transmembrane domain, including the cytoplasmic tail. By using P-element-mediated DNA transformation, the bossmel and bossvir genes were shown to rescue the D. melanogaster boss1 mutation. The expression of bossvir protein in D. melanogaster is indistinguishable from that of bossmel protein. Noncoding sequences which may regulate boss expression were identified based on their conservation during evolution. The predicted sev protein from D. virilis (sevvir) was previously shown to be 63% identical to sev from D. melanogaster (sevmel). A chimeric gene, (sevvir/mel), encoding the extracellular domain of sevvir and the cytoplasmic domain of sevmel rescues the D. melanogaster sevd2 mutation through interaction with either bossvir or bossmel.

Amino Acid Sequence↗

PubMed1995

Drosophila hormone receptor 38: a second partner for Drosophila USP suggests an unexpected role for nuclear receptors of the nerve growth factor-induced protein B type.

In Drosophila the response to the hormone ecdysone is mediated in part by Ultraspiracle (USP) and ecdysone receptor (EcR), which are members of the nuclear receptor superfamily. Heterodimers of these proteins bind to ecdysone response elements (EcREs) and ecdysone to modulate transcription. Herein we describe Drosophila hormone receptor 38 (DHR38) and Bombyx hormone receptor 38 (BHR38), two insect homologues of rat nerve growth factor-induced protein B (NGFI-B). Although members of the NGFI-B family are thought to function exclusively as monomers, we show that DHR38 and BHR38 in fact interact strongly with USP and that this interaction is evolutionarily conserved. DHR38 can compete in vitro against EcR for dimerization with USP and consequently disrupt EcR-USP binding to an EcRE. Moreover, transfection experiments in Schneider cells show that DHR38 can affect ecdysone-dependent transcription. This suggests that DHR38 plays a role in the ecdysone response and that more generally NGFI-B type receptors may be able to function as heterodimers with retinoid X receptor type receptors in regulating transcription.

Amino Acid Sequence↗

PubMed1997

Divergent and conserved features in the spatial expression of the Drosophila pseudoobscura esterase-5B gene and the esterase-6 gene of Drosophila melanogaster.

The regulatory regions of homologous genes encoding esterase 6 (Est-6) of Drosophila melanogaster and esterase 5B (Est-5B) of Drosophila pseudoobscura show very little similarity. We have undertaken a comparative study of the pattern of expression directed by the Est-5B and Est-6 5'-flanking DNA to attempt to reveal conserved elements regulating tissue-specific expression in adults. Esterase regulatory sequences were linked to a lacZ reporter gene and transformed into D. melanogaster embryos. Est-5B, 5' upstream elements, give rise to a beta-galactosidase expression pattern that coincides with the wild-type expression of Est-5B in D. pseudoobscura. The expression patterns of the Est-5B/lacZ construct are different from those of a fusion gene containing the upstream region of Est-6. Common sites of expression for both kinds of constructs are the third segment of antenna, the maxillary palps, and salivary glands. In vitro deletion mutagenesis has shown that the two genes have a different organization of regulatory elements controlling expression in both the third segment of antenna and maxillary palps. The results suggest that the conservation of the expression pattern in genes that evolved from a common ancestor may not be accompanied by preservation of the corresponding cis-regulatory elements.

Animals↗