Search results for "Transposon"
showing 10 items of 61 documents
Ty3/Gypsy Retrotransposons: Description of New Arabidopsis thaliana Elements and Evolutionary Perspectives Derived from Comparative Genomic Data
2000
We performed a comprehensive analysis of the evolution of the Ty3/GYPSY: group of long-terminal-repeat retrotransposons (also known as METAVIRIDAE:). Exhaustive database searches allowed us to detect novel elements of this group. In particular, the Arabidopsis thaliana and Drosophila melanogaster genome sequencing projects have recently disclosed a large number of new Ty3/GYPSY: sequences. So far, elements of three different Ty3/GYPSY: lineages had been described for A. thaliana. Here, we describe six new lineages, which we have called Tit-for-tat1, Tit-for-tat2, Gimli, Gloin, Legolas, and Little Athila. We confirm that plant Ty3/GYPSY: elements form two main monophyletic groups. Moreover, …
Tirant: A new retrotransposon-like element inDrosophila melanogaster
1996
In this paper we report a new retrotransposon-like element of Drosophila melanogaster called Tirant. This sequence is moderately repeated in the genome of this species and it has been found to be widely dispersed throughout its distribution area. From Southern blot and in situ analyses, this sequence appears to be mobile in D. melanogaster, since its chromosome location and the hybridization patterns vary among the different strains analyzed. In this way, partial sequencing of Tirant ends suggests that it is a retrotransposon, since it is flanked by two LTRs. The presence of sequences homologous to Tirant has been also investigated in 28 species of the genus Drosophila by means of Southern …
Identification and expression of Lactobacillus paracasei genes for adaptation to desiccation and rehydration
2018
AbstractLactobacillus paracaseiis able to persist in a variety of natural and technological environments despite physico-chemical perturbations, in particular alternations between desiccation and rehydration. However, the way in which it adapts to hydric fluctuations and in particular the genetic determinants involved are not clearly understood. To identify the genes involved in adaptation to desiccation, an annotated library ofL. paracaseirandom transposon mutants was screened for viability after desiccation (25% relative humidity, 25°C). Subsequently, the expression of the identified genes was measured at five stages of the dehydration-rehydration process to formulate the chronology of ge…
Sleeping Beauty transposon system – future trend in T-cell-based gene therapies?
2006
Evaluation of: Huang X, Wilber AC, Bao L et al.: Stable gene transfer and expression in human primary T cells by the Sleeping Beauty transposon system. Blood 107, 483–491 (2006). The Sleeping Beauty (SB) transposon system can mediate stable gene transfer and expression in primary human T cells. Optimal in vitro conditions for maximum gene transfer efficiencies have been developed with regard to further application of the SB transposon system in T cell based gene therapies. This raises the question of whether or not the SB transposon system is a convincing alternative for virus-mediated gene transfer based on the currently available data. Here, we will discuss controversial safety and effic…
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…
RNA-based regulation of transposon expression
2015
Throughout the domains of life, transposon activity represents a serious threat to genome integrity and evolution has realized different molecular mechanisms that aim to inhibit the transposition of mobile DNA. Small noncoding RNAs that function as guides for Argonaute effector proteins represent a key feature of so-called RNA interference (RNAi) pathways and specialized RNAi pathways exist to repress transposon activity on the transcriptional and posttranscriptional level. Transposon transcription can be diminished by targeted DNA methylation or chromatin remodeling via repressive Histone modifications. Posttranscriptional transposon silencing bases on degradation of transposon transcripts…
Recovery of mutants impaired in pathogenicity after transposition of Impala in Fusarium oxysporum f.sp. melonis
2000
The ability of transposon impala to inactivate genes involved in pathogenicity was tested in Fusarium oxysporum f. sp. melonis. Somatic excision of an impala copy inserted in the nitrate reductase-encoding niaD gene was positively selected through a phenotypic assay based on the restoration of nitrate reductase activity. Independent excision events were analyzed molecularly and shown to carry reinsertedimpala in more than 70% of the cases. Mapping of reinserted impala elements on large NotI-restriction fragments showed that impala transposes randomly. By screening 746 revertants on plants, a high proportion (3.5%) of mutants impaired in their pathogenic potential was recovered. According t…
A mammalian gene evolved from the integrase domain of an LTR retrotransposon.
2001
FIG. 1.—Summary of the structure and coding sequence of the human Gin-1 gene. Sequences of human cDNAs with accession numbers XMp003947.2 (a putative full-length cDNA), BE502574, AW173201.1, AW950418.1, AI631948.1, and AA766836.1 were used to deduce and confirm these data. The full-length protein is 522 amino acids long. The Gin-1 coding region spans nucleotides 36153–15345 in the genomic clone NTp002663.4. Arrowheads and the numbers above them, respectively, indicate the positions and lengths of introns. Several Alu repeats were detected within the two largest introns. Bold letters indicate the region homologous to the most conserved part of the IN domain, detailed in figure 2 and used to …
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 …
Structural analysis of Drosophila subobscura gypsy elements (gypsyDs)
1997
The study of gypsy elements in Drosophila subobscura (gypsyDs) indicated that they are transcriptionally active and mobile. From the comparative analysis of a complete gypsyDs element with the canonical gypsy sequence from D. melanogaster (gypsyDm) it can be deduced that while the whole structure is maintained, the gypsyDs ORF3 encodes a non-functional Env protein. The PCR amplification and sequencing of the ORF3 from different laboratory strains and H271 clones show that all gypsyDs sequences studied have frame-shifting mutations in this region. These results support that gypsyDs elements lack functional Env proteins and consequently they lack infective ability. In this way, it can be prop…