Kenji Ichiyanagi

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Genomic imprinting causes parental origin-specific monoallelic gene expression through differential DNA methylation established in the parental germ line. However, the mechanisms underlying how specific sequences are selectively methylated are not fully understood. We have found that the components of the PIWI-interacting RNA (piRNA) pathway are required(More)
Catalytic group II introns are mobile retroelements that invade cognate intronless genes via retrohoming, where the introns reverse splice into double-stranded DNA (dsDNA) targets. They can also retrotranspose to ectopic sites at low frequencies. Whereas our previous studies with a bacterial intron, Ll.LtrB, supported frequent use of RNA targets during(More)
Long interspersed elements (LINEs) are transposable elements that proliferate within eukaryotic genomes, having a large impact on eukaryotic genome evolution. LINEs mobilize via a process called retrotransposition. Although the role of the LINE-encoded protein(s) in retrotransposition has been extensively investigated, the participation of host-encoded(More)
Autonomous non-long terminal repeat retrotransposons (NLRs) are ubiquitous mobile genetic elements that insert their DNA copies at new locations by retrotransposition. In vertebrates, there are 4 NLR clades, L1, L2, CR1, and RTE, which diverged in the Precambrian era. It has been demonstrated that retrotransposition of L1 and L2 members proceeds via(More)
BACKGROUND Although there is lymphatic flow into the popliteal fossa from a skin tumor located in the lower leg, popliteal metastasis is extremely rare. Recently, sentinel lymph nodes outside traditional nodal basins have been identified. This study investigated the incidence of sentinel nodes in the popliteal region and the indication for biopsy. METHODS(More)
Inteins possess two different enzymatic activities, self-catalyzed protein splicing and site-specific DNA cleavage. These endonucleases, which are classified as part of the homing endonuclease family, initiate the mobility of their genetic elements into homologous alleles. They recognize long asymmetric nucleotide sequences and cleave both DNA strands in a(More)
Short interspersed elements (SINEs) are a class of retrotransposons, which amplify their copy numbers in their host genomes by retrotransposition. More than a million copies of SINEs are present in a mammalian genome, constituting over 10% of the total genomic sequence. In contrast to the other two classes of retrotransposons, long interspersed elements(More)
Group II introns, widely believed to be the ancestors of nuclear pre-mRNA introns, are catalytic RNAs found in bacteria, archaea, and eukaryotes. They are mobile genetic elements that move via an RNA intermediate. They retrohome to intronless alleles and retrotranspose to ectopic sites, aided by an intron-encoded protein with reverse transcriptase,(More)
DNA methylation is a well-characterized epigenetic modification involved in gene regulation and transposon silencing in mammals. It mainly occurs on cytosines at CpG sites but methylation at non-CpG sites is frequently observed in embryonic stem cells, induced pluriotent stem cells, oocytes and the brain. The biological significance of non-CpG methylation(More)
BACKGROUND Escherichia coli RuvC protein is a specific endonuclease that resolves Holliday junctions during homologous recombination. For junction resolution, RuvC undergoes distinct steps such as dimerization, junction-specific binding and endonucleolytic cleavage. The crystal structure of RuvC has been revealed. RESULTS To identify functionally(More)