Search results for "Elements"
showing 10 items of 799 documents
The evolutionary genetics of the hobo transposable element in the Drosophila melanogaster complex.
1994
Hobo elements are a family of transposable elements found in Drosophila melanogaster and its three sibling species: D. simulans, D. mauritiana and D. sechellia. Studies in D. melanogaster have shown that hobo may be mobilized, and that the genetic effects of such mobilizations included the general features of hybrid dysgenesis: mutations, chromosomal rearrangements and gonadal dysgenis in F1 individuals. At the evolutionary level some hobo-hybridizing sequences have also been found in the other members of the melanogaster subgroup and in many members of the related montium subgroup. Surveys of older collected strains of D. melanogaster suggest that complete hobo elements were absent prior t…
P sequences ofDrosophilla Subobscuralack exon 3 and may encode a 66 kd repressor-like protein
1991
Abstract Several P homologous sequences have been cloned and sequenced from Drosophila subobscura. These sequences are located at the 85DE region of the O chromosome and at least three of them are organized in tandem. We have identified four copies which exhibit strong similarity between them. All of the isolated elements are truncated at the 5' and 3' ends. They have lost the inverted terminal repeats and exon 3, but maintain exons 0, 1 and 2. They are transcribed producing a polyadenylated RNA. The structure of these transcripts suggests that they are able to encode a 66 kd repressor-like protein, but not a functional transposase. We ask about the biological role of a potential repressor …
Evolutionary transition to the ectomycorrhizal habit in the genomes of a hyperdiverse lineage of mushroom‐forming fungi
2022
International audience; Summary The ectomycorrhizal (ECM) symbiosis has independently evolved from diverse types of saprotrophic ancestors. In this study, we seek to identify genomic signatures of the transition to the ECM habit within the hyper-diverse Russulaceae. We present comparative analyses of the genomic architecture and the total and secreted gene repertoires of 18 species across the order Russulales of which 13 are newly sequenced, including a representative of a saprotrophic member of Russulaceae, Gloeopeniophorella convolvens. The genomes of ECM Russulaceae are characterized by a loss of genes for plant cell-wall degrading enzymes (PCWDEs), an expansion of genome size through in…
Tirant is a new member of the gypsy family of retrotransposons in Drosophila melanogaster.
2000
In this paper, we propose a consensus sequence for a putative complete Tirant retrotransposon. Several defective copies, as well as relevant sequences available in databases have been analyzed. The putative complete Tirant element is 8533 bp long, and presents all the structural features of a retroviruslike transposable element of the gypsy family. It contains three ORFs (open reading frames) that encode putative products resembling the retroviral Gag, Pol, and Env proteins. Southern blot analyses show that complete and defective Tirant elements are widespread in Drosophila melanogaster. The different hybridization patterns observed in several natural populations of this species suggest tha…
piRNAclusterDB 2.0: update and expansion of the piRNA cluster database.
2021
Abstract PIWI-interacting RNAs (piRNAs) and their partnering PIWI proteins defend the animal germline against transposable elements and play a crucial role in fertility. Numerous studies in the past have uncovered many additional functions of the piRNA pathway, including gene regulation, anti-viral defense, and somatic transposon repression. Further, comparative analyses across phylogenetic groups showed that the PIWI/piRNA system evolves rapidly and exhibits great evolutionary plasticity. However, the presence of so-called piRNA clusters as the major source of piRNAs is common to nearly all metazoan species. These genomic piRNA-producing loci are highly divergent across taxa and critically…
The Mu1 transposable element of maize contains two promoter signals recognized by the Escherichia coli RNA polymerase.
1990
The galactokinase (GalK) expression plasmid vector system pKO-1 has been used to screen for promoter elements in the maize transposable element Mu1 that function in Escherichia coli. Two transcriptional start points, named S1 and S2, were identified, which are located in the two direct repeats of the transposable element. This paper demonstrates that sequence elements exist in a plant transposable element which function as prokaryotic promotors.
bilbo, a non-LTR retrotransposon of Drosophila subobscura: a clue to the evolution of LINE-like elements in Drosophila
1997
We used the repetitive character of transposable elements to isolate a non-LTR retrotransposon in Drosophila subobscura. bilbo, as we have called it, has homology to TRIM and LOA elements. Sequence analysis showed a 5' untranslated region (UTR), an open reading frame (ORF) with no RNA-binding domains, a downstream ORF that had structural homology to that of the I factor, and, finally, a 3' UTR which ended in several 5-nt repeats. The results of our phylogenetic and structural analyses shed light on the evolution of Drosophila non-LTR retrotransposons and support the hypothesis that an ancestor of these elements was structurally complex.
Development of an Efficient In Vivo System (P-junc-TpaseIS(1223)) for Random Transposon Mutagenesis of Lactobacillus casei
2012
ABSTRACT The random transposon mutagenesis system P junc -TpaseIS 1223 is composed of plasmids pVI129, expressing IS 1223 transposase, and pVI110, a suicide transposon plasmid carrying the P junc sequence, the substrate of the IS 1223 transposase. This system is particularly efficient in Lactobacillus casei , as more than 10,000 stable, random mutants were routinely obtained via electroporation.
Drosophila melanogaster histone H2B retropseudogene is inserted into a region rich in transposable elements.
1998
We have isolated and characterized the genomic sequence of a Drosophila melanogaster histone H2B pseudogene that is localized outside of the cluster of the replication-dependent histone genes and has all the properties of a retropseudogene. It is highly homologous to the transcribed region of the D. melanogaster histone H2B gene, but not to its flanking regions, and is surrounded by short direct repeats. The pseudogene contains several point mutations that preclude its translation. The sequence of the 3' region of this pseudogene is compatible with the hypothesis that the 3' terminal stem-loop structure of the histone H2B mRNA has served as a primer for the reverse transcription event from …
The Genome of Cardinium cBtQ1 Provides Insights into Genome Reduction, Symbiont Motility, and Its Settlement in Bemisia tabaci
2014
International audience; Many insects harbor inherited bacterial endosymbionts. Although some of them are not strictly essential and are considered facultative, they can be a key to host survival under specific environmental conditions, such as parasitoid attacks, climate changes, or insecticide pressures. The whitefly Bemisia tabaci is at the top of the list of organisms inflicting agricultural damage and outbreaks, and changes in its distribution may be associated to global warming. In this work, we have sequenced and analyzed the genome of Cardinium cBtQ1, a facultative bacterial endosymbiont of B. tabaci and propose that it belongs to a new taxonomic family, which also includes Candidatu…