Horizontal transfer of OC1 transposons in the Tasmanian devil

BACKGROUND There is growing recognition that horizontal DNA transfer, a process known to be common in prokaryotes, is also a significant source of genomic variation in eukaryotes. Horizontal transfer of transposable elements (HTT) may be especially prevalent in eukaryotes given the inherent mobility, widespread occurrence, and prolific abundance of these elements in many eukaryotic genomes. RESULTS Here, we provide evidence for a new case of HTT of the transposon family OposCharlie1 (OC1) in the Tasmanian devil, Sarcophilus harrisii. Bioinformatic analyses of OC1 sequences in the Tasmanian devil genome suggest that this transposon infiltrated the common ancestor of the Dasyuridae family ~17 million years ago. This estimate is corroborated by a PCR-based screen for the presence/absence of this family in Tasmanian devils and closely-related species. CONCLUSIONS This case of HTT is the first to be reported in dasyurids. It brings the number of animal lineages independently invaded by OC1 to 12, and adds a fourth continent to the pandemic-like pattern of invasion of this transposon. In the context of these data, we discuss the evolutionary history of this transposon family and its potential impact on the diversification of marsupials.The authors would like to acknowledge the following organizations for funding portions of this work: NIH-R01 GM077582 (CF), M.J. Murdock Charitable Trust (SS) and NSF-MCB-1150213 (SS

Genomic impact of eukaryotic transposable elements

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Mobile DNA 3 (2012): 19, doi:10.1186/1759-8753-3-19.The third international conference on the genomic impact of eukaryotic transposable elements (TEs) was held 24 to 28 February 2012 at the Asilomar Conference Center, Pacific Grove, CA, USA. Sponsored in part by the National Institutes of Health grant 5 P41 LM006252, the goal of the conference was to bring together researchers from around the world who study the impact and mechanisms of TEs using multiple computational and experimental approaches. The meeting drew close to 170 attendees and included invited floor presentations on the biology of TEs and their genomic impact, as well as numerous talks contributed by young scientists. The workshop talks were devoted to computational analysis of TEs with additional time for discussion of unresolved issues. Also, there was ample opportunity for poster presentations and informal evening discussions. The success of the meeting reflects the important role of Repbase in comparative genomic studies, and emphasizes the need for close interactions between experimental and computational biologists in the years to come.The conference was supported in part by the National Institutes of Health grant 5 P41 LM006252

Meeting Report for Mobile DNA 2010

An international conference on mobile DNA was held 24-28 April 2010 in Montreal, Canada. Sponsored by the American Society for Microbiology, the conference's goal was to bring together researchers from around the world who study transposition in diverse organisms using multiple experimental approaches. The meeting drew over 190 attendees and most contributed through poster presentations, invited talks and short talks selected from poster abstracts. The talks were organized into eight scientific sessions, which ranged in topic from the evolutionary dynamics of mobile genetic elements to transposition reaction mechanisms. Here we present highlights from the platform sessions with a focus on talks presented by the invited speakers

Genomic DNA transposition induced by human PGBD5

Transposons are mobile genetic elements that are found in nearly all organisms, including humans. Mobilization of DNA transposons by transposase enzymes can cause genomic rearrangements, but our knowledge of human genes derived from transposases is limited. In this study, we find that the protein encoded by human PGBD5, the most evolutionarily conserved transposable element-derived gene in vertebrates, can induce stereotypical cut-and-paste DNA transposition in human cells. Genomic integration activity of PGBD5 requires distinct aspartic acid residues in its transposase domain, and specific DNA sequences containing inverted terminal repeats with similarity to piggyBac transposons. DNA transposition catalyzed by PGBD5 in human cells occurs genome-wide, with precise transposon excision and preference for insertion at TTAA sites. The apparent conservation of DNA transposition activity by PGBD5 suggests that genomic remodeling contributes to its biological function. DOI: http://dx.doi.org/10.7554/eLife.10565.00

Structure of the germline genome of Tetrahymena thermophila and relationship to the massively rearranged somatic genome

The germline genome of the binucleated ciliate Tetrahymena thermophila undergoes programmed chromosome breakage and massive DNA elimination to generate the somatic genome. Here, we present a complete sequence assembly of the germline genome and analyze multiple features of its structure and its relationship to the somatic genome, shedding light on the mechanisms of genome rearrangement as well as the evolutionary history of this remarkable germline/soma differentiation. Our results strengthen the notion that a complex, dynamic, and ongoing interplay between mobile DNA elements and the host genome have shaped Tetrahymena chromosome structure, locally and globally. Non-standard outcomes of rearrangement events, including the generation of short-lived somatic chromosomes and excision of DNA interrupting protein-coding regions, may represent novel forms of developmental gene regulation. We also compare Tetrahymenas germline/soma differentiation to that of other characterized ciliates, illustrating the wide diversity of adaptations that have occurred within this phylum.</p

Sequencing of Culex quinquefasciatus establishes a platform for mosquito comparative genomics

Culex quinquefasciatus (the southern house mosquito) is an important mosquito vector of viruses such as West Nile virus and St. Louis encephalitis virus, as well as of nematodes that cause lymphatic filariasis. C. quinquefasciatus is one species within the Culex pipiens species complex and can be found throughout tropical and temperate climates of the world. The ability of C. quinquefasciatus to take blood meals from birds, livestock, and humans contributes to its ability to vector pathogens between species. Here, we describe the genomic sequence of C. quinquefasciatus: Its repertoire of 18,883 protein-coding genes is 22% larger than that of Aedes aegypti and 52% larger than that of Anopheles gambiae with multiple gene-family expansions, including olfactory and gustatory receptors, salivary gland genes, and genes associated with xenobiotic detoxification

COMMENT NAISSENT LES ELEMENTS TRANSPOSABLES ? CARACTERISATION ET EVOLUTION DE FAMILLES NON AUTONOMES DE TYPE MITE ET SINE CHEZ LE MOUSTIQUE CULEX PIPIENS

NOUS AVONS CARACTERISE LE GENE WHITE DE CULEX PIPIENS ET MONTRE QUE LES INTRONS 1 ET 2 DE CE GENE SONT SIGNIFICATIVEMENT PLUS GRANDS QUE CHEZ LA PLUPART DES AUTRES ESPECES DE DIPTERES. NOS ANALYSES SUGGERENT QUE LA TAILLE DE CES INTRONS VARIE EGALEMENT AU SEIN DE L'ESPECE C. PIPIENS. NOUS AVONS DECOUVERT QU'AU MOINS ONZE ELEMENTS TRANSPOSABLES DIFFERENTS SE SONT RECEMMENT INSERES DANS LES INTRONS 1 ET 2 DU GENE WHITE DE LA SOUCHE TEM-R DE C. PIPIENS. CES RESULTATS REFLETENT LA MOBILISATION MASSIVE ET FREQUENTE DES ELEMENTS TRANSPOSABLES CHEZ CETTE ESPECE. PARADOXALEMENT, TOUS LES ELEMENTS ASSOCIES AU GENE WHITE DE C. PIPIENS SONT NON AUTONOMES. LA PLUPART APPARTIENNENT A DES FAMILLES JUSQU'ALORS INCONNUES CHEZ CETTE ESPECE ET RAREMENT DECRITES CHEZ LES INSECTES (MITES ET SINES). AFIN DE MIEUX COMPRENDRE COMMENT NAISSENT ET S'AMPLIFIENT CES ELEMENTS DEPOURVUS DE CAPACITE CODANTE, NOUS AVONS CARACTERISE EN DETAIL UNE FAMILLE DE SINES, TWIN, ET UNE FAMILLE DE MITES, MIMO. LA STRUCTURE INEDITE DES SINES TWIN SUGGERE QU'ILS PROVIENNENT DE LA RETROPOSITION D'UN TRANSCRIT CONTENANT DEUX GENES D'ARNT. LA STRUCTURE SECONDAIRE DE CE TRANSCRIT AURAIT FAVORISE SA RECONNAISSANCE PAR UNE TRANSCRIPTASE INVERSE CODEE AILLEURS DANS LE GENOME. LES MITES MIMO, QUANT A EUX, RESSEMBLENT A DES TRANSPOSONS DE CLASSE II NON AUTONOMES : PETITE TAILLE, REPETITIONS TERMINALES INVERSEES ET SPECIFICITE D'INSERTION POUR LA SEQUENCE TA. DE PLUS, LES EXTREMITES DE MIMO PRESENTENT DES SIMILARITES SIGNIFICATIVES AVEC D'AUTRES FAMILLES DE MITES (WUJIN D'AEDES AEGYPTI ET EMIGRANT D'ARABIDOPSIS THALIANA), MAIS AUSSI AVEC DES ELEMENTS DE LA SUPERFAMILLE TC1/MARINER (CLASSE II), ET EN PARTICULIER LE GROUPE POGO. CES OBSERVATIONS SUGGERENT QUE CES MITES ONT ETE MOBILISES PAR UNE TRANSPOSASE CODEE PAR UN ELEMENT DE TYPE POGO. POUR CONFIRMER CETTE HYPOTHESE, NOUS AVONS RECHERCHE DANS LA SEQUENCE COMPLETE DU GENOME D'A. THALIANA LA SOURCE DE TRANSPOSASE DES MITES EMIGRANT ET IDENTIFIE LEMIL, LE PREMIER REPRESENTANT POTENTIELLEMENT COMPLET DE LA FAMILLE POGO CHEZ LES PLANTES. NOTRE ANALYSE GENOMIQUE MONTRE QUE LA FAMILLE DE MITES EMIGRANT EST DERIVEE DE CE TRANSPOSON FOSSILE.PARIS-BIUSJ-Thèses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF