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PubMed1989

Purification and characterization of mRNA cap-binding protein from Drosophila melanogaster embryos.

A protein with specific affinity for the mRNA cap structure was purified both from the postribosomal supernatant and from the ribosomal high-salt wash of Drosophila melanogaster embryos by m7GTP-Sepharose chromatography. This protein had an apparent molecular mass of 35 kilodaltons (kDa) in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a size very different from those of the cap-binding proteins that have been characterized thus far. Drosophila 35-kDa cap-binding protein (CBP) could also be isolated from the ribosomal high-salt wash as part of a salt-stable protein complex consisting of polypeptides of 35, 72, and 140 to 180 kDa. Polyclonal antibodies against Drosophila 35-kDa CBP neither reacted with eucaryotic initiation factor 4E from rabbit reticulocytes nor affected mRNA translation in a rabbit reticulocyte cell-free system. However, in a cell-free system from Drosophila embryos, mRNA translation was specifically inhibited by these antibodies. The requirement of 35-kDa CBP for mRNA translation in Drosophila was diminished under ionic conditions in which the importance of mRNA cap structure recognition was reduced. Despite the structural differences between Drosophila 35-kDa CBP and mammalian initiation factor 4E, both proteins were functionally interchangeable in the in vitro translation system from Drosophila embryos.

Animals↗
PubMed2006

Heterologous expression of bovine rhodopsin in Drosophila photoreceptor cells.

PURPOSE: Vertebrate and invertebrate visual pigments are similar in amino acid sequence, structural organization, spectral properties, and mechanism of action, but possess different chromophores and trigger phototransduction through distinct biochemical pathways. The bovine opsin gene (Rho) was expressed in Drosophila, to examine the properties of a vertebrate opsin within invertebrate photoreceptor cells. METHODS: Transgenic Drosophila expressing the bovine opsin gene (Rho) in photoreceptors were created. Protein expression and cellular location of bovine rhodopsin was assessed by protein blots and immunofluorescence. The glycosylation state was determined by mobility profiles in SDS-PAGE before and after treatment with endoglycosidase. The rhodopsin chromophore was determined by HPLC-mass spectroscopy (MS) and the spectral properties by spectroscopy. The ability of the bovine rhodopsin to couple to Drosophila phototransduction components was assessed by electroretinography and to couple to vertebrate transducin by light-mediated GTPgammaS-binding assays. RESULTS: Rho showed stable expression even in the absence of endogenous Rh1 opsin and chromophore. It was correctly targeted to the rhabdomeric membranes. Rho remained glycosylated during the maturation process and possessed a distinct glycosylation pattern from that of native Rho. The Drosophila-expressed Rho associated with the 3-hydroxyretinal chromophore but failed to evoke an electroretinogram response from fly photoreceptors. However, the Drosophila-expressed Rho activated transducin in a light-dependent manner. CONCLUSIONS: Drosophila photoreceptors express a vertebrate rhodopsin as a functional visual pigment, but the expression does not activate the Drosophila phototransduction pathway. The system allows the characterization and comparison of vertebrate and invertebrate visual pigment properties in a common cell type.

Animals↗
PubMed1991

Signaling and regulation by a mammalian glucocorticoid receptor in Drosophila cells.

We demonstrate that the rat glucocorticoid receptor enhanced transcription in cultured Drosophila cells from Drosophila promoters linked to glucocorticoid response elements (GREs); promoters either containing or lacking a TATA box were rendered hormone inducible. Enhancement was dependent on the receptor, GREs, and the presence of an agonist ligand such as dexamethasone. The specific activities and relative efficacies of a series of potential ligands were generally similar in Drosophila and mammalian cells, except that dexamethasone mesylate, a potent antagonist in mammalian cells, was a strong agonist in Drosophila cells. A composite GRE, which mediates either positive or negative glucocorticoid regulation in animal cells depending on the presence and composition of the AP-1 transcription factor, conferred hormone-dependent enhancement, but not repression, in Drosophila cells. These results indicate that factors in addition to the receptor and GRE sequences participate as determinants of both signal transduction and transcriptional regulation by the glucocorticoid receptor, and that Drosophila cells carry functional homologs of many or all of those factors. Moreover, receptor activity can be exploited to obtain regulated gene expression in Drosophila.

Alcohol Dehydrogenase↗
PubMed2003

blistery encodes Drosophila tensin protein and interacts with integrin and the JNK signaling pathway during wing development.

Tensin is an actin-binding protein that is localized in focal adhesions. At focal adhesion sites, tensin participates in the protein complex that establishes transmembrane linkage between the extracellular matrix and cytoskeletal actin filaments. Even though there have been many studies on tensin as an adaptor protein, the role of tensin during development has not yet been clearly elucidated. Thus, this study was designed to dissect the developmental role of tensin by isolating Drosophila tensin mutants and characterizing its role in wing development. The Drosophila tensin loss-of-function mutations resulted in the formation of blisters in the wings, which was due to a defective wing unfolding process. Interestingly, by(1)-the mutant allele of the gene blistery (by)-also showed a blistered wing phenotype, but failed to complement the wing blister phenotype of the Drosophila tensin mutants, and contains Y62N/T163R point mutations in Drosophila tensin coding sequences. These results demonstrate that by encodes Drosophila tensin protein and that the Drosophila tensin mutants are alleles of by. Using a genetic approach, we have demonstrated that tensin interacts with integrin and also with the components of the JNK signaling pathway during wing development; overexpression of by in wing imaginal discs significantly increased JNK activity and induced apoptotic cell death. Collectively, our data suggest that tensin relays signals from the extracellular matrix to the cytoskeleton through interaction with integrin, and through the modulation of the JNK signal transduction pathway during Drosophila wing development.

Animals↗
PubMed2003

Biochemical characterization, distribution and phylogenetic analysis of Drosophila melanogaster ryanodine and IP3 receptors, and thapsigargin-sensitive Ca2+ ATPase.

We characterized the biochemistry, distribution and phylogeny of Drosophila ryanodine (RyR) and inositol triphosphate (IP3R) receptors and the endoplasmic reticulum Ca2+-ATPase (SERCA) by using binding and enzymatic assays, confocal microscopy and amino acid sequence analysis. [3H]-ryanodine binding in total membranes was enhanced by AMP-PCP, caffeine and xanthine, whereas Mg2+, Ruthenium Red and dantrolene were inhibitors. [3H]-ryanodine binding showed a bell-shaped curve with increasing free [Ca2+], without complete inhibition at millimolar levels of [Ca2+]. [3H]-IP3 binding was inhibited by heparin, 2-APB and xestospongin C. Microsomal Ca2+-ATPase activity was inhibited by thapsigargin. Confocal microscopy demonstrated abundant expression of ryanodine and inositol triphosphate receptors and abundant Ca2+-ATPase in Drosophila embryos and adults. Ryanodine receptor was expressed mainly in the digestive tract and parts of the nervous system. Maximum parsimony and Neighbour Joining were used to generate a phylogenetic classification of Drosophila ryanodine and insitol triphosphate receptors and Ca2+-ATPase based on 48 invertebrate and vertebrate complete sequences. The consensus trees indicated that Drosophila proteins grouped with proteins from other invertebrates, separately from vertebrate counterparts. Despite evolutionary distances, our functional results demonstrate that Drosophila ryanodine and inositol triphosphate receptors and Ca2+-ATPase are reasonably similar to vertebrate counterparts. Our protein expression data are consistent with the known functions of these proteins in the Drosophila digestive tract and nervous system. Overall, results show Drosophila as a valuable tool for intracellular Ca2+ dynamics studies in eukaryotes.

Animals↗
PubMed1992

Drosophila with postponed aging as a model for aging research.

Species of the genus Drosophila, commonly known as "fruitflies," are good model systems for research in aging. Drosophila are extremely well-known genetically, developmentally, and otherwise. They are also genetically analogous to mammalian species in most important respects. Previous work with Drosophila has been hampered by inbreeding depression, but more recent work using selection has created Drosophila with postponed aging that is inherited normally. Genetic transformation has also increased Drosophila life spans in some cases. Several biologic approaches have been applied to the analysis of genetically postponed aging in Drosophila: quantitative genetics, organismal physiology, and protein electrophoresis. Ultimately, these different approaches will be integrated into an overall analysis of aging in Drosophila, one that could be valuable for research with other taxa as well.

Aging↗
PubMed1992

[P transposable element in Drosophila melanogaster: horizontal transfer].

The P transposable element family in Drosophila melanogaster is responsible for the syndrome of hybrid dysgenesis which includes chromosomal rearrangements, male recombination, high mutability and temperature sensitive agametic sterility (called gonadal dysgenesis sterility). P element activity is controlled by a complex regulation system, encoded by the elements themselves, which keeps their transposition rate low within the strain bearing P elements and limits copy number by genome. A second regulatory mechanism, which acts on the level of RNA processing, prevents P mobility to somatic cells. The oldest available strains, representing most major geographical regions of the world, exhibited no detectable hybridization to the P-element. In contrast, all recently collected natural populations that were tested carried P-element sequences. The available evidence is consistent with the hypothesis of a worldwide P-element invasion of D. melanogaster during the past 30 years. Timing and direction of the invasion are discussed. The lack of P-element in older strains of Drosophila melanogaster as well as in the species must closely related to Drosophila melanogaster, suggests that P entered the Drosophila melanogaster genome recently, probably by horizontal transfer from an other species. The analysis of P-element elsewhere in the genus Drosophila reveals that several more distantly related species carried transposable elements with sequences quite similar to P. The species with the best-matching P-element is D. willistoni. A P-element from this species was found to match all but one of the 2907 nucleotides of the Drosophila melanogaster P-element. The phylogenic distributions and the likely horizontal transfers of the two other Drosophila transposable elements are discussed.

Animals↗
PubMed2003

[Effects of amino acids on the survival of heat-exposed Drosophila].

To investigate the effects of amino acids on the survival of heat-exposed Drosophila and to select the amino acids that can protect the Drosophila from heat exposure, Drosophila melanogaster were fed with basic culture in 25 degrees C. The male virgin Drosophilas were distinguished from female. Both male and female virgin Drosophilas were divided respectively to the trail groups and control group with randomization. The trail groups were fed with culture supplying different amino acids in 37.5 degrees C. After 10 hours, the dead insects were counted every two hours until all of them were dead. The mortality rates of heat-exposed Drosophilas that feed in the culture added with the glutamine, arginine, phenylalanine, tyrosine and glutamic acid were obviously higher than that of control. The glutamine, arginine, phenylalanine, tyrosine and glutamic acid might increase survival time of heat-exposed Drosophila, but a dose-response relationship was not observed.

Adaptation, Physiological↗
PubMed2005

Drosophila melanogaster--the model organism of choice for the complex biology of multi-cellular organisms.

Drosophila melanogaster has been intensely studied for almost 100 years. The sophisticated array of genetic and molecular tools that have evolved for analysis of gene function in this organism are unique. Further, Drosophila is a complex multi-cellular organism in which many aspects of development and behavior parallel those in human beings. These combined advantages have permitted research in Drosophila to make seminal contributions to the understanding of fundamental biological processes and ensure that Drosophila will continue to provide unique insights in the genomic era. An overview of the genetic methodologies available in Drosophila is given here, together with examples of outstanding recent contributions of Drosophila to our understanding of cell and organismal biology. The growing contribution of Drosophila to our knowledge of gravity-related responses is addressed.

Animals↗
PubMed1990

Drosophila proliferating cell nuclear antigen. Structural and functional homology with its mammalian counterpart.

A protein with an apparent mass of 36 kDa was purified from Drosophila melanogaster embryos using a protocol developed for the purification of proliferating cell nuclear antigen (PCNA) from human 293 cells. The Drosophila protein comigrated with human PCNA on one-dimensional sodium dodecyl sulfate-polyacrylamide gels and cross-reacted with monoclonal anti-rabbit PCNA antibodies. NH2-terminal amino acid sequence analysis revealed that the putative Drosophila PCNA was highly homologous to human PCNA. Of the first 22 amino acids, 16 were identical, and 4 of the remaining 6 were changed conservatively. Results of total amino acid analysis were also consistent with a high degree of similarity between Drosophila PCNA and human PCNA. Functional analysis using the reconstituted simian virus 40 in vitro DNA replication system demonstrated that Drosophila PCNA could substitute, albeit with reduced efficiency, for human PCNA in stimulating simian virus 40 DNA synthesis. Affinity-purified anti-Drosophila PCNA antibodies cross-reacted with human PCNA and were able to recognize specifically Drosophila PCNA both on crude homogenate immunoblots and by indirect immunofluorescence analysis of proliferating cells in larval tissues in situ. These antibodies thus promise to be useful probes for the study of cell proliferation in this rapidly developing organism.

Amino Acid Sequence↗
PubMed1986

Drosophila apurinic/apyrimidinic DNA endonucleases. Characterization of mechanism of action and demonstration of a novel type of enzyme activity.

Two species of apurinic/apyrimidinic (AP) endonuclease have been purified approximately 400-fold from extracts of Drosophila embryos. AP endonuclease I, which flows through phosphocellulose columns, has an apparent subunit molecular weight of 66,000 as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas AP endonuclease II, which is retained by phosphocellulose, has a subunit molecular weight of 63,000. The molecular weight determinations were made possible in part by the finding that both Drosophila enzymes, along with Escherichia coli endonuclease IV, cross-react with an antibody prepared toward a human AP endonuclease (Kane, C. M., and Linn, S. (1981) J. Biol. Chem. 256, 3405-3414). The nature of phosphodiester bond breaks produced by the two partially purified AP endonucleases from Drosophila have been investigated. Nicks introduced into partially depurinated PM2 DNA by Drosophila AP endonuclease I did not support DNA synthesis by E. coli DNA polymerase I, whereas nicks created by AP endonuclease II were able to support DNA synthesis, but at a rate far less than that observed for nicks introduced by E. coli endonuclease IV. The priming activity of DNA incised by either of the Drosophila enzymes can be enhanced, however, by an additional incubation with E. coli endonuclease IV, which is known to cleave depurinated DNA on the 5'-side of an apurinic site. These results suggest that the Drosophila enzymes cleave depurinated DNA on the 3'-side of the apurinic site. This suggestion was strengthened by the observation that the combined action of AP endonuclease II and E. coli endonuclease IV resulted in the removal of [32P]dAMP from partially depyrimidinated [dAMP-5'-32P,uracil-3H]poly(dA-dT). Taken together, these results propose that Drosophila AP endonuclease II produces 3'-deoxyribose and 5'-phosphomonoester nucleotide termini. Conversely, the absolute inability to detect priming activity for DNA cleaved by AP endonuclease I alone suggested a different mechanism, possibly the formation of a deoxyribose-3'-phosphate terminus. When apurinic DNA cleaved by AP endonuclease I was subsequently treated with bacterial alkaline phosphatase, DNA synthesis was now detected at levels similar to that observed for AP endonuclease II alone. Additionally, DNA nicked by AP endonuclease I was susceptible to 5'-end labeling by polynucleotide T4 kinase without prior phosphomonoesterase treatment. These results suggest that AP endonuclease I forms deoxyribose 3'-phosphate and 5'-OH termini upon cleaving depurinated DNA.

Animals↗
PubMed1998

Functional characterization of HLA-DRA1*0101/DRB1*0401 molecules expressed in Drosophila melanogaster cells.

We have expressed the human MHC class II molecule, HLA-DRA1*0101/-DRB1*0401 (DRB1*0401), in Drosophila melanogaster Schneider 2 cells under control of the Drosophila metallothionein promoter. Upon induction with CuSO4, flow cytometry revealed expression of DRB1*0401 on the surface of the Drosophila cells at high levels. The membrane-bound class II molecules could present peptides specifically to DRB1*0401-restricted T cells. Drosophila-expressed DRB1*0401 molecules revealed a decreased N-linked glycosylation as compared to DRB1*0401 molecules purified from a human B-cell line. The purified DRB1*0401 molecules from Drosophila cells were dissociated into subunits in SDS-PAGE but could be stabilized with a peptide known to bind DRB1*0401 with a high affinity, indicating that the recombinant class II molecules from Drosophila cells are either empty or occupied by low affinity endogenous peptides. This assumption was further substantiated by the observation that the class II molecules from Drosophila cells had a much higher peptide-binding capacity than DRB1*0401 molecules derived from the human B-cell line. Otherwise, the two species of DRB1*0401 had similar peptide-binding specificities and affinities. The purified recombinant DRB1*0401 molecules also showed biological activity because immobilized complexes of DRB1*0401 and synthetic peptides specifically stimulated DRB1*0401-restricted T cells.

Amino Acid Sequence↗
PubMed2026

Single-organ proteomics in Drosophila melanogaster larva.

The combination of genetic accessibility, organ complexity, evolutionary conservation, and cost-efficiency makes Drosophila melanogaster (Dm) a well-known model system for biomedical and fundamental biological research. Proteomic analysis of single organs enables the identification and quantification of proteins expressed in specific organs. This will help to uncover specific biological functions and unique protein profiles that are not detectable in whole-organism analyses. In this study we have isolated single organs form Dm larvae, and we have performed a deep proteomics mapping by following a minimal manipulation preparation procedure. The combined dataset across all organs comprised 9132 identified proteins. As anticipated, principal component analysis (PCA) revealed clear separation between the proteomes of most organs, confirming distinct protein profiles. These findings demonstrate the applicability of the sample preparation strategy for high-resolution proteomic characterization of individual organs in Drosophila. Given the extensive genetic tools available for this model organism, our approach has the potential to open new avenues for proteomic studies in Drosophila melanogaster and any other biological systems where the sample amount is limiting. SIGNIFICANCE STATEMENT: Drosophila melanogaster is a well-known model system for biomedical and fundamental biological research that serves as a valuable in vivo model organism due to its high degree of evolutionary conservation with higher vertebrates, tractable genetics, and logistical efficiency. However, the proteome of Drosophila at single organ level has been elusive to date, due to several factors like low sensitivity of previous generation mass spectrometers and sample preparation procedures, difficult isolation of some organs. In this study we have applied a compilation of advanced methods including minimal sample manipulation together with simple, straightforward and efficient protein extraction and digestion methods. Obtained peptides were minimally handled to be analyzed by applying specific and sensitive nLC methods coupled on-line to state-of-the-art MS/MS system. Altogether, the applied strategy allowed us to get the first single organ study to date for this animal. These datasets represent a significative resource for future genomic, transcriptomic and proteomic studies in Drosophila, as multi-omic integration requires deep proteomics to translate data into functional biochemistry, and serves as a critical bridge and an indispensable standalone resource across the genomic, transcriptomic, and proteomic landscapes.

Animals↗
PubMed2006

Adaptive protein evolution and regulatory divergence in Drosophila.

Two recent studies demonstrated a positive correlation between divergence in gene expression and protein sequence in Drosophila. This correlation could be driven by positive selection or variation in functional constraint. To distinguish between these alternatives, we compared patterns of molecular evolution for 1,862 genes with two previously reported estimates of expression divergence in Drosophila. We found a slight negative trend (nonsignificant) between positive selection on protein sequence and divergence in expression levels between Drosophila melanogaster and Drosophila simulans. Conversely, shifts in expression patterns during Drosophila development showed a positive association with adaptive protein evolution, though as before the relationship was weak and not significant. Overall, we found no strong evidence for an increase in the incidence of positive selection on protein-coding regions in genes with divergent expression in Drosophila, suggesting that the previously reported positive association between protein and regulatory divergence primarily reflects variation in functional constraint.

Amino Acid Sequence↗
PubMed1991

ADH and phylogenetic relationships of Drosophila lebanonesis (Scaptodrosophila).

Increasing data on Drosophila alcohol dehydrogenase (ADH) sequences have made it possible to calculate the rate of amino acid replacement per year, which is 1.7 x 10(-9). This value makes this protein suitable for reconstructing phylogenetic relationships within the genus for those species for which no molecular data are available such as Scaptodrosophila. The amino acid sequence of Drosophila lebanonensis is compared to all of the already known Drosophila ADHs, stressing the unique characteristic features of this protein such as the conservation of an initiating methionine at the N-terminus, the unique replacement of a glycine by an alanine at a very conserved position in the NAD domain of all dehydrogenases, the lack of a slow-migrating peptide, and the total conservation of the maximally hydrophilic peptide. The functional significance of these features is discussed. Although the percent amino acid identity of the ADH molecule in Drosophila decreases as the number of sequences compared increases, the conservation of residue type in terms of size and hydrophobocity for the ADH molecule is shown to be very high throughout the genus Drosophila. The distance matrix and parsimony methods used to establish the phylogenetic relationships of D. lebanonensis show that the three subgenera, Scaptodrosophila, Drosophila, and Sophophora separated at approximately the same time.

Alcohol Dehydrogenase↗
PubMed2003

Sex determination in Drosophila melanogaster and Musca domestica converges at the level of the terminal regulator doublesex.

Sex-determining cascades are supposed to have evolved in a retrograde manner from bottom to top. Wilkins' 1995 hypothesis finds support from our comparative studies in Drosophila melanogaster and Musca domestica, two dipteran species that separated some 120 million years ago. The sex-determining cascades in these flies differ at the level of the primary sex-determining signal and their targets, Sxl in Drosophila and F in Musca. Here we present evidence that they converge at the level of the terminal regulator, doublesex ( dsx), which conveys the selected sexual fate to the differentiation genes. The dsx homologue in Musca, Md-dsx, encodes male-specific (MdDSX(M)) and female-specific (MdDSX(F)) protein variants which correspond in structure to those in Drosophila. Sex-specific regulation of Md-dsx is controlled by the switch gene F via a splicing mechanism that is similar but in some relevant aspects different from that in Drosophila. MdDSX(F) expression can activate the vitellogenin genes in Drosophila and Musca males, and MdDSX(M) expression in Drosophila females can cause male-like pigmentation of posterior tergites, suggesting that these Musca dsx variants are conserved not only in structure but also in function. Furthermore, downregulation of Md-dsx activity in Musca by injecting dsRNA into embryos leads to intersexual differentiation of the gonads. These results strongly support a role of Md-dsx as the final regulatory gene in the sex-determining hierarchy of the housefly.

Amino Acid Sequence↗
PubMed2005

Regulation of cell adhesion in the Drosophila embryo by phosphorylation of the cadherin-catenin-complex.

Cell-culture studies indicate that tyrosine phosphorylation of the cadherin-catenin-complex (CCC) is one of the post-translational mechanism regulating E-cadherin-mediated cell adhesion. In this investigation, controlled application of a tyrosine phosphatase inhibitor (orthovanadate) and tyrosine kinase inhibitor (tyrphostin) to early Drosophila embryos, followed by biochemical assays and phenotypic analysis, has been utilized to address the mechanism by which tyrosine phosphorylation regulates E-cadherin-mediated cell adhesion in vivo. Our data suggest that, in the Drosophila embryo, beta-catenin (Drosophila homolog Armadillo) is the primary tyrosine-phosphorylated protein in the CCC. The increase in tyrosine phosphorylation correlates with a loss of epithelial integrity and adherens junctions in the ectoderm of early embryos. Late application of the phosphatase inhibitor does not have this effect, presumably because of the formation of septate junctions in late embryos. Co-immunoprecipitation assays have demonstrated that tyrosine hyper-phosphorylation does not cause the dissociation of Drosophila (D)E-cadherin and alpha-catenin or Armadillo, suggesting that abrogation in adhesion is most likely attributable to the detachment of actin-associated proteins from the CCC. Finally, although the Drosophila epidermal growth factor receptor (EGFR), a receptor tyrosine kinase, is linked to the CCC and shows genetic interactions with DE-cadherin, we find that a constitutively active Drosophila EGFR construct does not cause any detectable changes in the level of tyrosine phosphorylation of Armadillo or destabilization of the CCC.

Animals↗
PubMed2005

Two retrotransposons maintain telomeres in Drosophila.

Telomeres across the genus Drosophila are maintained, not by telomerase, but by two non-LTR retrotransposons, HeT-A and TART, that transpose specifically to chromosome ends. Successive transpositions result in long head-to-tail arrays of these elements. Thus Drosophila telomeres, like those produced by telomerase, consist of repeated sequences reverse transcribed from RNA templates. The Drosophila repeats, complete and 5'-truncated copies of HeT-A and TART, are more complex than telomerase repeats; nevertheless, these evolutionary variants have functional similarities to the more common telomeres. Like other telomeres, the Drosophila arrays are dynamic, fluctuating around an average length that can be changed by changes in the genetic background. Several proteins that interact with telomeres in other species have been found to have homologues that interact with Drosophila telomeres. Although they have hallmarks of non-LTR retrotransposons, HeT-A and TART appear to have a special relationship to Drosophila. Their Gag proteins are efficiently transported into diploid nuclei where HeT-A Gag recruits TART Gag to chromosome ends. Gags of other non-LTR elements remain predominantly in the cytoplasm. These studies provide intriguing evolutionary links between telomeres and retrotransposable elements.

Animals↗