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PubMed2002

Isolation, characterization, and localization of beta-tubulin genomic clones of three Drosophila montium subgroup species.

Genomic libraries were constructed from three Drosophila species, namely Drosophila auraria, Drosophila serrata, and Drosophila kikkawai, belonging to the Drosophila montium subgroup of the Drosophila melanogaster species group. Clones containing beta-tubulin specific sequences were isolated, characterized by restriction endonuclease digestions and Southern hybridizations, and mapped by in situ hybridization on the polytene chromosomes of the species studied. The distribution of the beta-tubulin loci was found to be similar in D. montium species and D. melanogaster.

Animals↗
PubMed1996

A new P element subfamily from Drosophila tristis, D. ambigua, and D. obscura.

A new P element subfamily, designated T-type, was found in the genomes of the three closely related species Drosophila ambigua, Drosophila obscura, and Drosophila tristis. The subfamily comprises both full-sized and internally deleted P elements. The T-type element of D. ambigua is longer than the canonical P elements owing to a 300-bp insertion in the 3' noncoding region. Tandemly arranged T-type elements were detected in D. ambigua and D. tristis. The overall structure of T-type elements resembles that of the Drosophila melanogaster P element and the termini are formed by perfect inverted repeats of 33 bp. However, none of the elements studied so far have intact reading frames. Sequence comparisons with other P element subfamilies from the obscura group indicate that the T-type elements are most closely related to the terminally truncated P homologues of Drosophila guanche and Drosophila subobscura. Therefore they can be considered as the lineage-specific P transposons of the obscura group. Furthermore, this finding indicates that the clustered P homologues of D. guanche and D. subobscura must be derived from transpositionally active P elements rather than from an immobile genomic sequence.

Animals↗
PubMed2002

Comparative modeling of the phosphatase and kinase domains of protein tyrosine phosphatase and insulin receptor kinase from Drosophila melanogaster (DPTP61fm), and a computational study of their mutual interactions.

The components and functions of the insulin receptor kinase signaling pathway have been conserved in a broad range of Metazoa ranging from mammals to insects and nematodes. There is a high degree of sequence homology and functional similarity between the human insulin receptor kinase (IRK) and the drosophila (Drosophila melanogaster) form (DIRK) of this enzyme. Similarly, a high degree of homology exists between human protein tyrosine phosphatase 1B (PTP1B) (which directly regulates IRK) and its drosophila counterpart DPTP61F (DPTP). However, genetic and biochemical studies have yet to demonstrate that DPTP61F acts in the DIRK pathway. Comparative structural modeling techniques using the known structures of human IRK and PTP1B as templates have yielded structures for the drosophila enzymes. The derived structures confirm that there is a high level of structural conservation at the tertiary level. Association of the DIRK and DPTP enzymes with each other was then investigated with a view to ascertaining whether DIRK might be a substrate of the DPTP. Evaluation of the interaction surfaces, including hydrophobic patch, shape, hydrogen bonding, and electrostatic compatibility, strongly suggested that the drosophila insulin receptor is a substrate of the DPTP. The interaction surfaces of the human and drosophila enzymes are structurally similar, although changes in critical residues modify possible electrostatic and hydrogen-bonding interactions. This suggests that in the mixed systems, DPTP-IRK or PTP1B-DIRK, the kinase domain will be a comparatively poor substrate for phosphatase activity when compared with the native systems.

Amino Acid Sequence↗
PubMed1983

The major heat-shock protein (hsp70) gene family: related sequences in mouse, Drosophila, and yeast.

Heat shock induces the synthesis of a 70-kdalton protein in Escherichia coli, Drosophila, yeast, and mouse. We show that the genes for this heat-shock protein in mouse, yeast, and Drosophila share extensive sequence homology as determined by heteroduplex formation at different stringencies. We calculate that the heat-shock gene homology is 74% between yeast and Drosophila and 85% between mouse and Drosophila. The organization of the six copies of the Drosophila gene for the 70-kdalton heat-shock protein at two separate loci is summarized and evidence is presented that the yeast and mouse genomes each contain multiple copies of sequences related to the Drosophila gene for the 70-kdalton heat-shock protein. These results demonstrate that not only the sequence but also the repetitive organization of the major heat-shock genes is conserved.

Animals↗
PubMed1999

Limit cycle models for circadian rhythms based on transcriptional regulation in Drosophila and Neurospora.

We examine theoretical models for circadian oscillations based on transcriptional regulation in Drosophila and Neurospora. For Drosophila, the molecular model is based on the negative feedback exerted on the expression of the per and tim genes by the complex formed between the PER and TIM proteins. For Neurospora, similarly, the model relies on the feedback exerted on the expression of the frq gene by its protein product FRQ. In both models, sustained rhythmic variations in protein and mRNA levels occur in continuous darkness, in the form of limit cycle oscillations. The effect of light on circadian rhythms is taken into account in the models by considering that it triggers degradation of the TIM protein in Drosophila, and frq transcription in Neurospora. When incorporating the control exerted by light at the molecular level, we show that the models can account for the entrainment of circadian rhythms by light-dark cycles and for the damping of the oscillations in constant light, though such damping occurs more readily in the Drosophila model. The models account for the phase shifts induced by light pulses and allow the construction of phase response curves. These compare well with experimental results obtained in Drosophila. The model for Drosophila shows that when applied at the appropriate phase, light pulses of appropriate duration and magnitude can permanently or transiently suppress circadian rhythmicity. We investigate the effects of the magnitude of light-induced changes on oscillatory behavior. Finally, we discuss the common and distinctive features of circadian oscillations in the two organisms.

Algorithms↗
PubMed2004

Heterologous expression of plant virus genes that suppress post-transcriptional gene silencing results in suppression of RNA interference in Drosophila cells.

BACKGROUND: RNA interference (RNAi) in animals and post-transcriptional gene silencing (PTGS) in plants are related phenomena whose functions include the developmental regulation of gene expression and protection from transposable elements and viruses. Plant viruses respond by expressing suppressor proteins that interfere with the PTGS system. RESULTS: Here we demonstrate that both transient and constitutive expression of the Tobacco etch virus HC-Pro silencing suppressor protein, which inhibits the maintenance of PTGS in plants, prevents dsRNA-induced RNAi of a lacZ gene in cultured Drosophila cells. Northern blot analysis of the RNA present in Drosophila cells showed that HC-Pro prevented degradation of lacZ RNA during RNAi but that there was accumulation of the short (23nt) RNA species associated with RNAi. A mutant HC-Pro that does not suppress PTGS in plants also does not affect RNAi in Drosophila. Similarly, the Cucumber mosaic virus 2b protein, which inhibits the systemic spread of PTGS in plants, does not suppress RNAi in Drosophila cells. In addition, we have used the Drosophila system to demonstrate that the 16K cysteine-rich protein of Tobacco rattle virus, which previously had no known function, is a silencing suppressor protein. CONCLUSION: These results indicate that at least part of the process of RNAi in Drosophila and PTGS in plants is conserved, and that plant virus silencing suppressor proteins may be useful tools to investigate the mechanism of RNAi.

Animals↗
PubMed2003

Comparison of K+-channel genes within the genomes of Anopheles gambiae and Drosophila melanogaster.

BACKGROUND: Potassium channels are the largest and most diverse type of ion channel found in nature. The completion of the sequencing of the genomes of Drosophila melanogaster and Anopheles gambiae, which belong to the same order, the Diptera, allows us to compare and contrast K+-channel genes and gene families present within the genomes of two dipterans. RESULTS: This study identifies at least eight voltage-gated K+-channel genes in Anopheles, as well as three Slo-family, three Eag-family and six inward rectifier K+-channel genes. The genomic organization of K+-channel genes from Drosophila and Anopheles is well conserved. The sequence identity of the most similar K+-channel gene products between these two species ranges from 42% to 98%, with a mean value of 85%. Although most K+-channel genes in Drosophila and Anopheles are present in a 1:1 ratio, Anopheles has more genes in three K+-channel types, namely KQT, Kv3, and inward rectifier channels. Microsynteny between the genes flanking K+-channel genes in Drosophila and Anopheles was seldom observed; however, most of the K+-channel genes are indeed located at positions which a previous genome-wide comparison has designated as homologous chromosomal regions. CONCLUSIONS: The Anopheles genome encodes more voltage-gated and inward rectifier K+-channel genes than that of Drosophila. Despite the conservation of intron-exon boundaries, orthologs of genes flanking K+-channel genes in Drosophila are generally not found adjacent to the Anopheles K+-channel orthologs, suggesting that extensive translocation of genes has occurred since the divergence of these two organisms.

Amino Acid Sequence↗
PubMed1992

Isolation and expression of two novel Wnt/wingless gene homologues in Drosophila.

Wingless (wg), the Drosophila homologue of the mouse Wnt-1 proto-oncogene, is a segment polarity gene essential in each segment for normal Drosophila development. We here report the isolation of two novel Drosophila Wnt homologues, DWnt-2 and DWnt-3, and thus the existence of a Wnt/wingless gene family in Drosophila. DWnt-2 and DWnt-3 map to chromosome 2 position 45E and chromosome X position 17A/B, respectively. DWnt-2 and DWnt-3, like the other known Wnt genes, encode amino-terminal signal peptides suggesting that the gene products are secreted proteins. The putative translation product of DWnt-2 and the carboxy-terminal half of the deduced DWnt-3 product are both rich in conserved cysteine residues. In comparison with other Wnt gene products, mostly about 40 x 10(3) relative molecular mass, the DWnt-3 protein has an extended amino terminus and a long internal insert, and its predicted relative molecular mass is 113 x 10(3). The expression patterns of these two Wnt/wg homologues are dynamic during Drosophila embryogenesis. The distribution of DWnt-2 transcripts is predominantly segmented, with the additional presence of transcripts in the presumptive gonads. Transcripts of both DWnt-2 and DWnt-3 appear to be associated with limb primordia in the embryo and may therefore specify limb development. DWnt-3 is also expressed in mesodermal and neurogenic regions. The distribution of DWnt-3 transcripts in cells of the central nervous system (CNS) during Drosophila embryogenesis suggests that DWnt-3 could be involved in CNS development.

Amino Acid Sequence↗
PubMed2005

Regulation of mitosis in response to damaged or incompletely replicated DNA require different levels of Grapes (Drosophila Chk1).

Checkpoints monitor the state of DNA and can delay or arrest the cell cycle at multiple points including G1-S transition, progress through S phase and G2-M transition. Regulation of progress through mitosis, specifically at the metaphase-anaphase transition, occurs after exposure to ionizing radiation (IR) in Drosophila and budding yeast, but has not been conclusively demonstrated in mammals. Here we report that regulation of metaphase-anaphase transition in Drosophila depends on the magnitude of radiation dose and time in the cell cycle at which radiation is applied, which may explain the apparent differences among experimental systems and offer an explanation as to why this regulation has not been seen in mammalian cells. We further document that mutants in Drosophila Chk1 (Grapes) that are capable of delaying the progress through mitosis in response to IR are incapable of delaying progress through mitosis when DNA synthesis is blocked by mutations in an essential replication factor encoded by double park (Drosophila Cdt1). We conclude that DNA damage and replication checkpoints operating in the same cell cycle at the same developmental stage in Drosophila can exhibit differential requirements for the Chk1 homolog. The converse situation exists in fission yeast where loss of Chk1 is more detrimental to the DNA damage checkpoint than to the DNA replication checkpoint. It remains to be seen which of these two different uses of Chk1 homologs are conserved in mammals. Finally, our results demonstrate that Drosophila provides a unique opportunity to study the regulation of the entry into, and progress through, mitosis by DNA structure checkpoints in metazoa.

Anaphase↗
PubMed1999

The Drosophila GMII gene encodes a Golgi alpha-mannosidase II.

In this paper we show the organisation of the Drosophila gene encoding a Golgi alpha-mannosidase II. We demonstrate that it encodes a functional homologue of the mouse Golgi alpha-mannosidase II. The Drosophila and mouse cDNA sequences translate into amino acid sequences which show 41% identity and 61% similarity. Expression of the Drosophila GMII sequence in CHOP cells produces an enzyme which has mannosidase activity and is inhibited by swainsonine and by CuSO(4.) In cultured Drosophila cells and in Drosophila embryos, antibodies raised against a C-terminal peptide localise this product mainly to the Golgi apparatus as identified by cryo-immuno electron microscopy studies and by antibodies raised against known mammalian Golgi proteins. We discuss these results in terms of the possible use of dGMII as a Drosophila Golgi marker.

Adaptor Protein Complex alpha Subunits↗
PubMed2004

No effects of chlorophyllin on IQ (2-amino-3-methylimidazo[4,5-f]-quinoline)-genotoxicity and -DNA adduct formation in Drosophila.

Previously we demonstrated that chlorophyllin suppressed the genotoxicities of many carcinogens. However, the genotoxicity of IQ (2-amino-3-methylimidazo[4,5-f]quinoline), a carcinogenic heterocyclic amine, was not suppressed in Drosophila. On the contrary, it has been reported that chrolophyllin suppressed the genotoxicity of IQ in rodents, rainbow trout and Salmonella. We demonstrated that the chlorophyllin-induced suppression of MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline)-genotoxicity was associated with a decrease in MeIQx-DNA adduct formation in Drosophila larval DNA. MeIQx represents another type of heterocyclic amine and is similar to IQ in structure. In this study we utilized (32)P-postlabeling to examine whether chlorophyllin reduced IQ-DNA adduct formation in Drosophila DNA in the same way as MeIQx. The results revealed that the formation of IQ-DNA adducts was unaffected by treatment with chlorophyllin. This was consistent with the absence of any inhibitory effect on genotoxicity as observed in the Drosophila repair test. These results suggest that IQ-behavior in Drosophila is not affected by chlorophyllin, indicating that the process of IQ-DNA adduct formation followed by expression of genotoxicity in Drosophila may be different from that in other organisms.

Animals↗
PubMed1997

The isolation, localization and characterization of the QM homolog in Drosophila melanogaster.

A fragment of 443 bp was amplified from a lambda ZAPII Drosophila central nervous system (CNS) cDNA library using minimally degenerate primers to very conserved regions of the QM gene. This fragment was used as a probe to screen the lambda ZAPII Drosophila CNS cDNA library. Two clones of the Drosophila QM homolog (pDQM-7A1 and pDQM-2B1), each containing the complete coding region, were isolated. The 5'-UTR of this gene was obtained by RACE PCR and ligated to the coding sequence to produce a the full-length copy of the Drosophila QM homolog (DQM) cDNA. The DQM cDNA measures 746 nucleotides in length and encodes a polypeptide of 218 residues. The amino acid sequence shows 76.1 percent identity with human QM and 69.1 percent identity with QSR1, the yeast homolog of QM. Unlike the human or mouse genome which contains multiple copies of the QM gene, the Drosophila genome has only a single copy as indicated by genomic Southern blot analysis. In situ hybridization confirms the presence of a single copy of DQM in the Drosophila genome and localizes it to the left arm of the third chromosome at the end of region 80A (80A-4).

Amino Acid Sequence↗
PubMed2002

[Molecular phylogeny of Drosophila auraria species complex].

Drosophila auraria species complex consists of five sibling species D. auraria, D. biauraria, D. triauraria, D. quadraria and D. subauraria. The complete sequences of nuclear ITS1 (internal transcribed specer 1) and mitochondrial CO II (Cytochrome Oxdase II), and partial sequences of nuclear Adh (alcohol dehydrogenase) of these five sibling species and their closely-related species, D. rufa, were determined. Using D. rufa, D. melanogaster and D. yukuba as outgroups, both most-parsimony (MP) and neighbor-joining (NJ) trees were constructed based on the sequences of each genetic marker. In each tree, D. subauraria always branched off first within Drosophila auraria species complex. Combined sequences of ITS1, Adh and CO II are 2327 bp (excluding gaps), of which 255 sites are parsimony informative. Phylogenetic analyses based on the combined data sets can resolve the phylogenetic relationships of the five sibling species relatively well. According to the MP and NJ trees based on the combined sequences, D. subauraria was the first to emerge within Drosophila auraria species complex, thereafter D. biauraria branched off, D. auraria, D. triauraria and D. quadraria had a relatively recent speciation history. In this paper we propose a hypothesis about divergence events in Drosophila auraria species complex: The ancestor of this species complex diverged with D. rufa in warm-temperate regions about 2.33 myr ago, then they invaded into cold-temperate regions. In cold-temperate regions, D. subauraria was firstly derived from the ancestor of Drosophila auraria species complex about 0.88 myr ago, thereafter D. biauraria emerged about 0.31 myr ago. During the process the ancestor reinvading into warm-temperate and subtropical regions, speciations of D. auraria, D. triauraria and D. quadraria were gradually completed. This hypothesis does not agree on the previous opinion that D. quadraria was the ancestral species of Drosophila auraria species complex.

Alcohol Dehydrogenase↗
PubMed2002

Female remating, sperm competition and sexual selection in Drosophila.

Female remating is fundamental to evolutionary biology as it determines the pattern of sexual selection and sexual conflict. Remating in females is an important component of Drosophila mating systems because it affects sperm usage patterns and sexual selection. Remating is common in females of many species of Drosophila in both natural and laboratory populations. It has been reported in many insect species and also in vertebrates. Female remating is a prerequisite for sperm competition between males, and the consequences of this competition, such as sperm precedence or sperm displacement, have been reported for many species of Drosophila. Female remating is dependent on the amount of sperm stored, the male seminal fluid components, nutrition, the quantity of eggs laid, experimental design and density of flies in laboratory. Remating by a female is an insurance against male sterility and sub-fertility and increases genetic heterogeneity of female offspring. Remating gives greater female productivity in many species of Drosophila. We examined female remating with respect to sperm competition and sexual selection in Drosophila and addressed the possible benefits for females. We also reviewed the role of accessory gland fluid in remating, costs associated with remating, the genetic basis of female remating and some possible mechanisms of sperm competition in the light of last male sperm priority and paternity assurance in Drosophila and other insects. We also suggest future areas of research.

Animals↗
PubMed1991

The Drosophila RBP-J kappa gene encodes the binding protein for the immunoglobulin J kappa recombination signal sequence.

We previously isolated a cDNA encoding the 60-kDa murine protein (RBP-J kappa protein) that specifically binds to the immunoglobulin J kappa recombination signal sequence. The RBP-J kappa gene is highly conserved in a wide variety of organisms including man, Xenopus, Drosophila, and yeast. We have isolated and characterized the Drosophila homologue of the RBP-J kappa gene. The Drosophila RBP-J kappa gene was mapped to the polytene region 35BC of chromosome 2. The nucleotide sequence of this gene indicates that it is not one of the known genes located in the 35 BC region. The nucleotide and amino acid sequences of the Drosophila and mouse RBP-J kappa genes are 60 and 75% homologous, respectively. The central 248-residue regions of RBP-J kappa proteins of the two species are 93% homologous and include the 40-residue integrase motif. The Drosophila RBP-J kappa protein expressed in COS cells bound to the J kappa recognition sequence with the same specificity as the murine counterpart. These results suggest that Drosophila may have a site-specific recombination system which utilizes the immunoglobulin recombination signal sequence. Implications for evolution of immunoglobulin gene rearrangement were also discussed.

Amino Acid Sequence↗
PubMed1990

Immunolocalization of G protein alpha-subunits in the Drosophila CNS.

In order to uncover the role of G proteins in the integrative functioning and development of the nervous system, we have begun a multidisciplinary study of the G proteins present in the fruit fly, Drosophila melanogaster. In this report, we describe the distribution of 3 different G protein alpha-subunits in the adult Drosophila CNS as determined by immunocytochemical localization using affinity-purified antibodies generated to synthetic oligopeptide sequences unique to each alpha-subunit. Western blot analysis of membranes prepared from Drosophila heads indicates that antibodies specific for the Drosophila Go alpha and Gs alpha homologs recognize the appropriate protein species predicted by molecular cloning (Quan et al., 1989; Thambi et al., 1989). The Gi alpha homolog could not be detected in head membranes by Western blotting, consistent with the negligible levels of expression observed for Gi alpha on Northern blots of head mRNA (Provost et al., 1988). However, a Drosophila Gi alpha fusion protein could be detected by these antibodies following expression in E. coli. Immunolocalization studies revealed that the Go alpha and Gs alpha homologs are expressed at highest levels in neuropils and at intermediate levels in the cortex of all brain and thoracic ganglion areas. Only the lamina contained low levels of these alpha-subunits in the CNS. Additionally, Gs alpha appears to be associated with the cell membranes of neuronal cell bodies, while Go alpha has a more diffuse distribution, suggesting its presence in the cytoplasm as well as cell membranes. In contrast to the wide distribution of Go alpha and Gs alpha, Gi alpha has a surprisingly restricted distribution in the CNS. It is present at high levels only in photoreceptor cell terminations, glomerulae of the antennal lobes, and the ocellar retina. Little or no Gi alpha was detected in other brain regions or in the thoracic ganglion. Gi alpha, then, appears to be uniquely associated with some primary sensory afferents and their terminations, suggesting the presence of specific receptor and/or effector systems which mediate the transmission of primary sensory information in Drosophila.

Animals↗
PubMed1987

Structure, organization, and transcription of Drosophila U6 small nuclear RNA genes.

U6 RNA is an abundant, capped small nuclear RNA (snRNA) associated with hnRNP particles (Reddy, R., and Busch, H. (1983) Prog. Nucleic Acid Res. Mol. Biol. 30, 127-162). Small nuclear ribonucleoprotein particles containing U4 and U6 RNAs are required components for splicing of pre-mRNAs (Berget and Robberson, 1986; Black and Steitz, 1986). In this study the Drosophila U6 RNA genes have been isolated and characterized. The Drosophila genome contains three U6 snRNA genes which are clustered in a 2-kilobase-pairs long DNA fragment. The U6 RNA coding regions are 100% homologous in all three genes, but the flanking sequences diverged significantly from each other. A possible secondary structure model for the Drosophila U4/U6 RNA complex is presented. Consistent with our previous observation that U6 RNA is a RNA polymerase III product (Reddy, R., Henning, D., Das, G., Harless, M., and Wright, D. (1987) J. Biol. Chem. 262, 75-81), all three genes contained a region homologous to the consensus intragenic regulatory region and a cluster of T residues on the 3'-end, characteristic of genes transcribed by RNA polymerase III. A TATA box was found between nucleotides -23 and -31, and a stretch of 28 nucleotides from -43 to -71 was conserved in the 5'-flanking region of all three U6 RNA genes. The Drosophila U6 RNA genes were transcribed in vitro by Drosophila nuclear extracts but were not transcribed by Novikoff hepatoma or HeLa cell extracts. Similarly, a mouse U6 RNA gene was transcribed in Novikoff hepatoma or HeLa cell extracts but not in Drosophila nuclear extracts. These results suggest that species-specific factor(s) are involved in the transcription of U6 snRNA genes.

Animals↗
PubMed1987

Analysis of the 5' end of the Drosophila muscle myosin heavy chain gene. Alternatively spliced transcripts initiate at a single site and intron locations are conserved compared to myosin genes of other organisms.

We have localized the transcription start site of the Drosophila melanogaster muscle myosin heavy chain (MHC) gene and find that all forms of the alternatively spliced MHC mRNA initiate at the same location. Therefore the alternative inclusion/exclusion of the 3' penultimate exon in transcripts from this gene (Bernstein, S.I., Hansen, C.J., Becker, K.D., Wassenberg, D.R., II, Roche, E.S., Donady, J.J., and Emerson, C. P., Jr. (1986) Mol. Cell. Biol. 6, 2511-2519; Rozek, C.E., and Davidson, N. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 2128-2134) does not result from the use of different 5' transcription initiation sites. This gene is the first invertebrate MHC gene shown to have TATA and CAAT box consensus sequences and a noncoding 5' exon, properties that are shared with some vertebrate and invertebrate contractile protein genes. The intron that splits the 5' noncoding region of the Drosophila MHC gene contains no major conserved elements relative to other Drosophila contractile protein genes. The introns within the coding region near the 5' end of the Drosophila MHC gene are located at the same sites as nematode and vertebrate MHC gene introns, indicating that these MHC genes are derived from a common ancestral sequence. The putative ATP binding domain encoded in the fourth exon of the Drosophila MHC gene is highly conserved relative to vertebrate, invertebrate, and non-muscle MHC genes suggesting that each of these myosins bind ATP by the same mechanism. Two divergent copies of the third exon are present within the 5' region of the Drosophila MHC gene, suggesting that alternative splicing produces MHC isoforms with different globular head regions.

Amino Acid Sequence↗