Tardigrades, also known as water bears, are small aquatic animals. Some tardigrade species tolerate almost complete dehydration and exhibit extraordinary tolerance to various physical extremes in the dehydrated state. Here we determine a high-quality genome sequence of Ramazzottius varieornatus, one of the most stress-tolerant tardigrade species. Precise gene repertoire analyses reveal the presence of a small proportion (1.2% or less) of putative foreign genes, loss of gene pathways that promote stress damage, expansion of gene families related to ameliorating damage, and evolution and high expression of novel tardigrade-unique proteins. Minor changes in the gene expression profiles during dehydration and rehydration suggest constitutive expression of tolerance-related genes. Using human cultured cells, we demonstrate that a tardigrade-unique DNA-associating protein suppresses X-ray-induced DNA damage by ∼40% and improves radiotolerance. These findings indicate the relevance of tardigrade-unique proteins to tolerability and tardigrades could be a bountiful source of new protection genes and mechanisms.
The whole genome of Jatropha curcas was sequenced, using a combination of the conventional Sanger method and new-generation multiplex sequencing methods. Total length of the non-redundant sequences thus obtained was 285 858 490 bp consisting of 120 586 contigs and 29 831 singlets. They accounted for ∼95% of the gene-containing regions with the average G + C content was 34.3%. A total of 40 929 complete and partial structures of protein encoding genes have been deduced. Comparison with genes of other plant species indicated that 1529 (4%) of the putative protein-encoding genes are specific to the Euphorbiaceae family. A high degree of microsynteny was observed with the genome of castor bean and, to a lesser extent, with those of soybean and Arabidopsis thaliana. In parallel with genome sequencing, cDNAs derived from leaf and callus tissues were subjected to pyrosequencing, and a total of 21 225 unigene data have been generated. Polymorphism analysis using microsatellite markers developed from the genomic sequence data obtained was performed with 12 J. curcas lines collected from various parts of the world to estimate their genetic diversity. The genomic sequence and accompanying information presented here are expected to serve as valuable resources for the acceleration of fundamental and applied research with J. curcas, especially in the fields of environment-related research such as biofuel production. Further information on the genomic sequences and DNA markers is available at .
RodZ interacts with MreB and both factors are required to maintain the rod shape of Escherichia coli. The assembly of MreB into filaments regulates the subcellular arrangement of a group of enzymes that synthesizes the peptidoglycan (PG) layer. However, it is still unknown how polymerization of MreB determines the rod shape of bacterial cells. Regulatory factor(s) are likely to be involved in controlling the function and dynamics of MreB. We isolated suppressor mutations to partially recover the rod shape in rodZ deletion mutants and found that some of the suppressor mutations occurred in mreB. All of the mreB mutations were in or in the vicinity of domain IA of MreB. Those mreB mutations changed the property of MreB filaments in vivo. In addition, suppressor mutations were found in the periplasmic regions in PBP2 and RodA, encoded by mrdA and mrdB genes. Similar to MreB and RodZ, PBP2 and RodA are pivotal to the cell wall elongation process. Thus, we found that mutations in domain IA of MreB and in the periplasmic domain of PBP2 and RodA can restore growth and rod shape to ΔrodZ cells, possibly by changing the requirements of MreB in the process.
In order to upgrade the genome sequence information of J. curcas L., we integrated de novo assembly of a total of 537 million paired-end reads generated from the Illumina sequencing platform into the current genome assembly which was obtained by a combination of the conventional Sanger method and the Roche/454 sequencing platform. e total length of the upgraded genome sequences thus obtained was 297,661,187 bp consisting of 39,277 contigs. e average and N50 lengths of the generated contigs were 7,579 bp and 15,950 bp, both of which were increased fourfold from the previous genome assembly. Along with genome sequence upgrading, the currently available transcriptome data were collected from the public databases and assembled into 19,454 tentative consensus sequences. Based on a comparison between these tentative consensus sequences of transcripts and the predictions of computer programs, a total of 30,203 complete and partial structures of protein-encoding genes were deduced. e number of genes with complete structures was increased about threefold from the previous genome annotation. By applying the upgraded genome sequence and predicted proteincoding gene information, the number and features of the tandemly arrayed genes, syntenic relations between Jatropha and other plant genomes, and structural features of transposable elements were investigated. e detailed information on the updated J. curcas genome is available at http://www.kazusa.or.jp/jatropha/. Key words:Jatropha curcas, genome sequencing, transcriptome sequences, tentative consensus sequence, tandem gene duplication, database.Jatropha curcas L. is a perennial small tree or large shrub that belongs to the Euphorbiaceae family. J. curcas is endemic to central America but is distributed throughout the tropics and subtropics of Asia and Africa. J. curcas is an important non-edible oilseed crop with great potential for the production of biodiesel fuel. Since J. curcas is an undomesticated plant, its positive attributes in terms of breeding and utilization are not fully understood.In order to accelerate its genetic improvement, it is desirable to understand the genome information of J. curcas. With this goal in mind, we have analyzed the genome sequence of J. curcas by applying combined sequencing methods, and have made the obtained sequence information available through the public and web databases.e accumulated genome information (JAT_r3.0) was 285,858,490 bp consisting of 120,586 contigs and 29,831 singlets, and this accounted for approximately 95% of the gene-containing regions. A total of 40,929 complete and partial structures of proteinencoding genes have been deduced on the accumulated genome sequences. However, the majority of the predicted genes were partially predicted ones as the contig lengths were relatively short in JAT_r3.0. Further improvement of the genome sequence information is therefore needed.Along with the genome sequence approach, several transcriptome analyses have been attempted. Natarajan et al. have reported 12,084 ESTs using...
Oryzias latipes (medaka) has been established as a vertebrate genetic model for more than a century and recently has been rediscovered outside its native Japan. The power of new sequencing methods now makes it possible to reinvigorate medaka genetics, in particular by establishing a near-isogenic panel derived from a single wild population. Here we characterize the genomes of wild medaka catches obtained from a single Southern Japanese population in Kiyosu as a precursor for the establishment of a near-isogenic panel of wild lines. The population is free of significant detrimental population structure and has advantageous linkage disequilibrium properties suitable for the establishment of the proposed panel. Analysis of morphometric traits in five representative inbred strains suggests phenotypic mapping will be feasible in the panel. In addition, high-throughput genome sequencing of these medaka strains confirms their evolutionary relationships on lines of geographic separation and provides further evidence that there has been little significant interbreeding between the Southern and Northern medaka population since the Southern/Northern population split. The sequence data suggest that the Southern Japanese medaka existed as a larger older population that went through a relatively recent bottleneck approximately 10,000 years ago. In addition, we detect patterns of recent positive selection in the Southern population. These data indicate that the genetic structure of the Kiyosu medaka samples is suitable for the establishment of a vertebrate near-isogenic panel and therefore inbreeding of 200 lines based on this population has commenced. Progress of this project can be tracked at http://www.ebi.ac.uk/birney-srv/medaka-ref-panel.
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