[en] The Mutator (MuDR/Mu) DNA transposon family in maize includes diverse elements; they all share similar ∼215 bp Terminal Inverted Repeats (TIRs), but each has unique internal sequences. MuDR is the regulatory element for the entire system, and the presence of transcriptionally active MuDR elements is required for transposition of the nonautonomous Mu elements. MuDR encodes two genes, mudrA and mudrB. mudrA encodes the transposase, MURA, and mudrB encodes a protein with unknown function. In a previous work, we demonstrated that both mudrA and mudrB transcripts are expressed at higher levels after an 8h-UV-B treatment, in both Mutator active and silencing plants. This transcript increase is accompanied by an increase in histone H3 acetylation and by a decrease in DNA and histone H3 methylation. No changes in the siRNAs were detected. To further evaluate the role of UV-B in activating Mutator, we performed Chromatin Immunoprecipitation (ChIP) analysis using polyclonal antibodies specific for MURA to assess the in vivo binding capacity of the transposase to its target site in the Mu TIRs. We found that UV-B irradiation induces the binding of MURA to MuDR TIR in both active and silencing plant leaves. In addition, using plants containing a modified transposon RescueMu, we found that at least in Mutator active plants, novel excision events occur after 8h UV-B treatments. (authors)

[en] Short communication

No abstract available

[en] Repetitive genomic elements were prospected in Campomanesia xanthocarpa, aiming to characterize these elements in a non-model plant species and to develop species-specific microsatellite markers. Approximately 4.12% of the partial genome of C. xanthocarpa is composed of repetitive elements, being retrotransposons the most widely represented. A total of nine polymorphic microsatellite markers were obtained: four nuclear-neutral, two nuclear EST, two plastidial and one mitochondrial. Levels of population genetic diversity of four natural populations of C. xanthocarpa were characterized using these markers. In addition, the cross-species amplification of the microsatellite markers was tested in seven species of tribe Myrteae (Myrtaceae). The characterized microsatellite markers revealed low to moderate levels of genetic diversity (expected heterozygosity range: 0.33–0.57; observed heterozygosity: 0.26–0.74 and number of alleles: 2.25–4.25). Cross-species amplification was successful for all loci, except Cxant76. These nine markers will contribute for studies on genetic diversity, gene flow, plant selection and breeding of this species, towards the conservation of natural populations, as well as its commercial use.

[en] The Sleeping Beauty transposon (SB-Tn) system is being used widely as a DNA vector for the delivery of therapeutic transgenes, as well as a tool for the insertional mutagenesis in animal models. In order to accurately assess the insertional potential and properties related to the integration of SB it is essential to determine the copy number of SB-Tn in the host genome. Recently developed SB100X transposase has demonstrated an integration rate that was much higher than the original SB10 and that of other versions of hyperactive SB transposases, such as HSB3 or HSB17. In this study, we have constructed a series of SB vectors carrying either a DsRed or a human β-globin transgene that was encompassed by cHS4 insulator elements, and containing the SB100X transposase gene outside the SB-Tn unit within the same vector in cis configuration. These SB-Tn constructs were introduced into the K-562 erythroid cell line, and their presence in the genomes of host cells was analyzed by Southern blot analysis using non-radioactive probes. Many copies of SB-Tn insertions were detected in host cells regardless of transgene sequences or the presence of cHS4 insulator elements. Interestingly, the size difference of 2.4 kb between insulated SB and non-insulated controls did not reflect the proportional difference in copy numbers of inserted SB-Tns. We then attempted methylation-sensitive Southern blots to assess the potential influence of cHS4 insulator elements on the epigenetic modification of SB-Tn. Our results indicated that SB100X was able to integrate at multiple sites with the number of SB-Tn copies larger than 6 kb in size. In addition, the non-radioactive Southern blot protocols developed here will be useful to detect integrated SB-Tn copies in any mammalian cell type.

[en] The hobo transposable element of Drosophila melanogaster has been used to achieve stable germ line transformation of this insect. It is examined whether this element, or related transposable elements, can be used as vectors for achieving the germ line transformation of two non-drosophilids, the Australian sheep blowfly, Lucilia cuprina, and the housefly, Musca domestica. Through the use of excision assays designed to measure the mobility of hobo in prebastoderm embryos, it is demonstrated that this transposable element is capable of movement in these species and that this mobility is independent of the supplied hobo tranposase, suggesting the presence of host encoded factors which are capable of interacting with hobo DNA. The presence of hobo like elements in the genomes of each of these insects is supported by the cloning of hobo like sequences from both these species. Analysis of these sequences is discussed, as is the possible role of hobo and hobo like elements in achieving non-drosophilid germ line transformation. (author). 13 refs, 1 tab

No abstract available

No abstract available

[en] The Juan elements constitute a family of LINE's retroposons which are dispersed in the genome of many strains, if not all, of the three mosquito species A. Aegypti, C. pipiens and C. tarsalis. A specific Juan subfamily is amplified and dispersed in the genome of each of these species. They have been designated respectively as Juan A in A. aegypti, Juan C in C. pipiens and Juan Ct in C. tarsalis. The distribution of Juan retroposons among mosquito species does not reflect the phylogeny of these species. Furthermore, the Juan retroposons form homogeneous subfamilies: full-length copies which are reiterated in strains collected from regions covering different continents are nearly identical. These data are interpreted to indicate that the Juan retroposons have spread recently in the mosquito genomes harbouring them, perhaps upon horizontal transfer from other species. Juan A elements have been found in two isolates of A. albopictus and one isolate of A. polynesiensis, whereas numerous other isolates of these two species are devoided of any Juan-like sequence. The unfrequent presence of Juan A elements in some strains of A. albopictus and A. polynesiensis can be the result of an horizontal invasion, but more probably from cross-hybridizations which have been reported sometimes to occur between the former species and A. aegypti. No progeny is obtained when A. albopictus males containing Juan A retroposons are crossed with females lacking these elements, whereas the reciprocal cross is fertile. Such results suggest that the Juan retroposons may be responsible for incompatibilities between strains. (author). 19 refs, 1 fig., 1 tab

[en] The purpose of this project is development of world-class headspring techniques of biological science for application of plant genomes/epigenomes through study on radiation-responsive epigenomes and improvement of the national competitiveness in the field of fundamental technology for biological science and industry. Research scope includes 1) Investigation of radiation-responsive epigenomes and elucidation of their relation with phenotypes, 2) Elucidation of interaction and transcription control of epigenomes and epigenetic regulators using IR, 3) Investigation of epigenome-mediated traits in plant development, differentiation and antioxidant defense using IR, and 4) Development of application techniques of radiation-responsive epigenomes for eco-monitoring and molecular breeding. Main results are as follow: Investigation of radiation-responsive epigenomes, elucidation of relevance between DNA methylation and histone modification by gamma irradiation, investigation of radiation-specific epigenetic regulators, promoter analysis of the radiation-specific inducible gene, AtAGO2, investigation of transposable elements (TE) expression by gamma irradiation, development of radiation-responsive common markers of functional genomics, investigation of molecular functions in the gamma-ray inducible AT4G22960, investigation of the effects of plants by epigenetic inhibitors and gamma irradiation, investigation of physiological functions of radiation-specific inducible AtAGO2, development of transgenic plant using epigenetic regulators.