Search results for "Transposable elements"
showing 10 items of 68 documents
Clostridium difficile IStron CdISt1: Discovery of a Variant Encoding Two Complete Transposase-Like Proteins
2004
ABSTRACT Screening a Clostridium difficile strain collection for the chimeric element Cd ISt1 , we identified two additional variants, designated Cd ISt1 -0 and Cd ISt1 -III. In in vitro assays, we could prove the self-splicing ribozyme activity of these variants. Structural comparison of all known Cd ISt1 variants led us to define four types of IStrons that we designated Cd ISt1 -0 through Cd ISt1 -III. Since Cd ISt1 -0 encodes two complete transposase-like proteins (TlpA and TlpB), we suggest that it represents the original genetic element, hypothesized before to have originated by fusion of a group I intron and an insertion sequence element.
New Foldback transposable element TFB1 found in histone genes of the midge Chironomus thummi
1990
A new Foldback transposable element (TFB1) has been found in the histone H1-H3 intergenic region in the midge Chironomus thummi thummi. TFB1 has long terminal inverted repeats, composed of short, degenerate subrepeats and is flanked by nine or ten base-pair “target site” duplications. TFB1 is present in at least two adjacent histone gene units in Ch. th. thummi, indicating a homogenization of histone gene repeats. The copy number and chromosomal distribution of TFB1 are different in the closely related subspecies Ch. th. thummi and Ch. th. piger, showing that amplification, elimination and transposition of TFB1 have occurred recently during evolution.
Transposons Tn916 and Tn925 can transfer from Enterococcus faecalis to Leuconostoc oenos
1996
The streptococcal transposons Tn916 and Tn925 were transferred to several strains of Leuconostoc (Ln.) oenos using the filter mating method. The insertion of both transposons into the chromosome occurred at different sites. Transconjugants of Ln. oenos carrying Tn916 could serve as donors in mating experiments with Lactococcus lactis LM2301. Further analysis of L. lactis LM2301 transconjugants showed that the insertion of the transposon Tn916 into the chromosome was site-specific. These studies establish a basis for the initiation of genetic studies in this Leuconostoc species since there are no efficient conjugal or transformation systems previously described for this microorganism.
Demonstration that the Group II Intron from the Clostridial Conjugative Transposon Tn5397 Undergoes Splicing In Vivo
2001
Previous work has identified the conjugative transposon Tn5397 from Clostridium difficile. This element was shown to contain a group II intron. Tn5397 can be conjugatively transferred from C. difficile to Bacillus subtilis. In this work we show that the intron is spliced in both these hosts and that nonspliced RNA is also present. We constructed a mutation in the open reading frame within the intron, and this prevented splicing but did not prevent the formation of the circular form of the conjugative transposon (the likely transposition intermediate) or decrease the frequency of intergeneric transfer of Tn5397. Therefore, the intron is spliced, but splicing is not required for conjugation o…
Sequences homologous to the hobo transposable element in E strains of Drosophila melanogaster.
2001
Hobo is one of the three Drosophila melanogaster transposable elements, together with the P and I elements, that seem to have recently invaded the genome of this species. Surveys of the presence of hobo in strains from different geographical and temporal origins have shown that recently collected strains contain complete and deleted elements with high sequence similarity (H strains), but old strains lack hobo elements (E strains). Besides the canonical hobo sequences, both H and E strains show other poorly known hobo-related sequences. In the present work, we analyze the presence, cytogenetic location, and structure of some of these sequences in E strains of D. melanogaster. By in situ hybr…
Classification of prokaryotic genetic replicators: between selfishness and altruism
2015
Prokaryotes harbor a variety of genetic replicators, including plasmids, viruses, and chromosomes, each having different effects on the phenotype of the hosting cell. Here, we propose a classification for replicators of bacteria and archaea on the basis of their horizontal-transfer potential and the type of relationships (mutualistic, symbiotic, commensal, or parasitic) that they have with the host cell vehicle. Horizontal movement of replicators can be either active or passive, reflecting whether or not the replicator encodes the means to mediate its own transfer from one cell to another. Some replicators also have an infectious extracellular state, thus separating viruses from other mobil…
Molecular evolution of P transposable elements in the Genus drosophila. II. The obscura species group.
1998
A phylogenetic analysis of P transposable elements in the Drosophila obscura species group is described. Multiple P sequences from each of 10 species were obtained using PCR primers that flank a conserved region of exon 2 of the transposase gene. In general, the P element phylogeny is congruent with the species phylogeny, indicating that the dominant mode of transmission has been vertical, from generation to generation. One manifestation of this is the distinction of P elements from the Old World obscura and subobscura subgroups from those of the New World affinis subgroup. However, the overall distribution of elements within the obscura species group is not congruent with the phylogenetic …
Distribution of gypsy sequences in Drosophila species of the obscura subgroup.
2004
Eight Drosophila species of the obscura subgroup were screened for sequences homologous to the gypsy retrotransposon of D. melanogaster. Molecular characterization of gypsy sequences was first approached through digesting genomic DNAs from these obscura species with appropriate restriction enzymes and subjecting them to Southern blot analysis. The results of this analysis indicate that gypsy-homologous sequences are well conserved among species of the obscura subgroup. With the exception of D. guanche, all other species bear a 7 kb Xho I fragment that represents the complete element in D. melanogaster. Lower molecular weight fragments that could be deleted elements, are shared by different …
Centromeric enrichment of LINE-1 retrotransposon in two species of South American monkeys Alouatta belzebul and Ateles nancymaae (Platyrrhini, Primat…
2022
LINE-1 sequences have been linked to genome evolution, plasticity and speciation; however, despite their importance, their chromosomal distribution is poorly known in primates. In this perspective, we used fluorescence in situ hybridization (FISH) to map LINE-1 probes onto two representative platyrrhine species, Aotus nancymaae (Cebidae) and Alouatta belzebul (Atelidae), both characterized with highly rearranged karyotypes, in order to investigate their chromosomal distribution and role and to better characterize the two genomes. We found centromeric enrichment of LINE-1 sequences on all biarmed and acrocentric chromosomes co-localized with heterochromatin C-positive bands. This distributio…
Taste, movement, and death: varying effects of new prospero mutants during Drosophila development
2003
0022-3034 (Print) Comparative Study Journal Article Research Support, Non-U.S. Gov't; The PGal4 transposon inserted upstream of the pan-neural gene prospero (pros) causes several neural and behavioral defects in the Voila(1) strain. The precise excision of the transposon simultaneously rescued all these defects whereas its unprecise excision created new pros(V) alleles, including the null allele pros(V17). Here, we describe the relationship between the genetic structure of pros locus, larval locomotion, and larval gustatory response. These two behaviors showed varying degrees of variation depending upon the pros allele. We also found a good relation between behavioral alteration, the level …