Hidetoshi Tahara

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Secreted membrane-enclosed vesicles, collectively called extracellular vesicles (EVs), which include exosomes, ectosomes, microvesicles, microparticles, apoptotic bodies and other EV subsets, encompass a very rapidly growing scientific field in biology and medicine. Importantly, it is currently technically challenging to obtain a totally pure EV fraction(More)
The terminal t-loop structure adopted by mammalian telomeres is thought to prevent telomeres from being recognized as double-stranded DNA breaks by sequestering the 3' single-stranded G-rich overhang from exposure to the DNA damage machinery. The POT1 (protection of telomeres) protein binds the single-stranded overhang and is required for both chromosomal(More)
UV-sensitive syndrome (UV(S)S) is an autosomal recessive disorder characterized by photosensitivity and deficiency in transcription-coupled repair (TCR), a subpathway of nucleotide-excision repair that rapidly removes transcription-blocking DNA damage. Cockayne syndrome is a related disorder with defective TCR and consists of two complementation groups,(More)
Cellular senescence acts as a barrier to cancer progression, and microRNAs (miRNAs) are thought to be potential senescence regulators. However, whether senescence-associated miRNAs (SA-miRNAs) contribute to tumor suppression remains unknown. Here, we report that miR-22, a novel SA-miRNA, has an impact on tumorigenesis. miR-22 is up-regulated in human(More)
Cancer-prone syndrome of premature chromatid separation (PCS syndrome) with mosaic variegated aneuploidy (MVA) is a rare autosomal recessive disorder characterized by growth retardation, microcephaly, childhood cancer, premature chromatid separation of all chromosomes, and mosaicism for various trisomies and monosomies. Biallelic BUB1B mutations were(More)
The p16(INK4a) cyclin-dependent kinase inhibitor has a key role in establishing stable G1 cell-cycle arrest through activating the retinoblastoma (Rb) tumour suppressor protein pRb in cellular senescence. Here, we show that the p16(INK4a) /Rb-pathway also cooperates with mitogenic signals to induce elevated intracellular levels of reactive oxygen species(More)
To study cellular characteristics of human cementoblasts using a cellular model is important for understanding the mechanisms of homeostasis and regeneration of periodontal tissues. However, at present no immortalized human cementoblast cell line has been established due to limitation of the life span. In the present study, therefore, we attempted to(More)
The ATM- and Rad3-related (ATR) kinase is a master regulator of the DNA damage response, yet how ATR is activated toward different substrates is still poorly understood. Here, we show that ATR phosphorylates Chk1 and RPA32 through distinct mechanisms at replication-associated DNA double-stranded breaks (DSBs). In contrast to the rapid phosphorylation of(More)
Fanconi anemia (FA) is a rare genetic disorder characterized by genome instability, increased cancer susceptibility, progressive bone marrow failure (BMF), and various developmental abnormalities resulting from the defective FA pathway. FA is caused by mutations in genes that mediate repair processes of interstrand crosslinks and/or DNA adducts generated by(More)
Epstein-Barr virus (EBV) is closely associated with the generation of various tumors, including Burkitt's lymphoma. Human resting B cells from peripheral blood are easily transformed by EBV to actively proliferating B-lymphoblastoid cell lines (LCLs). These LCLs with normal diploid karyotypes have been believed to be "immortal", without becoming(More)