Kazuo Kinoshita

Learn More
Induced overexpression of AID in CH12F3-2 B lymphoma cells augmented class switching from IgM to IgA without cytokine stimulation. AID deficiency caused a complete defect in class switching and showed a hyper-IgM phenotype with enlarged germinal centers containing strongly activated B cells before or after immunization. AID-/- spleen cells stimulated in(More)
The activation-induced cytidine deaminase (AID) gene, specifically expressed in germinal center B cells in mice, is a member of the cytidine deaminase family. We herein report mutations in the human counterpart of AID in patients with the autosomal recessive form of hyper-IgM syndrome (HIGM2). Three major abnormalities characterize AID deficiency: (1) the(More)
BACKGROUND & AIMS Most gastrointestinal stromal tumors (GISTs) have gain-of-function mutations of c-kit receptor tyrosine kinase (KIT) gene, but some GISTs do not. We investigated the cause of GISTs without KIT mutations. Because GISTs apparently expressed platelet-derived growth factor receptor (PDGFR) alpha, we examined whether GISTs without KIT mutations(More)
Immunoglobulin A (IgA) is generated in the gut by both T cell-dependent and T cell-independent processes. The sites and the mechanisms for T cell-independent IgA synthesis remain elusive. Here we show that isolated lymphoid follicles (ILFs) were sites where induction of activation-induced cytidine deaminase (AID) and IgA class switching of B cells took(More)
Class switch recombination (CSR) and somatic hypermutation (SHM) have been considered to be mediated by different molecular mechanisms because both target DNAs and DNA modification products are quite distinct. However, involvement of activation-induced cytidine deaminase (AID) in both CSR and SHM has revealed that the two genetic alteration mechanisms are(More)
Activation-induced cytidine deaminase (AID), a putative RNA-editing enzyme, is indispensable for somatic hypermutation (SHM), class switch recombination, and gene conversion of immunoglobulin genes, which indicates a common molecular mechanism for these phenomena. Here we show that ectopic expression of AID alone can induce hypermutation in an artificial(More)
Fifty-five patients with high-grade advanced gastric cancer in whom the presence of stage IV was confirmed by preoperative diagnostic imaging were treated with PMUE therapy by a combined use of cisplatin (CDDP) 75 mg/m2, mitomycin C (MMC) 10 mg/body, etoposide 150 mg/body, and UFT (a combination of 1-(2-tetrahydrofuryl)-5-fluorouracil and uracil in a molar(More)
BACKGROUND After endoscopic submucosal dissection (ESD) of early gastric cancer (EGC), patients are at high risk for synchronous or metachronous multiple gastric cancers. OBJECTIVE To elucidate the time at which multiple cancers develop and to determine whether scheduled endoscopic surveillance might control their development. DESIGN A multicentre(More)
Both class switch recombination (CSR) and somatic hypermutation (SHM) of the Ig genes require the activity of activation-induced cytidine deaminase (AID). Expression of AID is restricted to B cells in the germinal centers of the lymphoid organs, where activated B cells undergo CSR and SHM. We previously showed that constitutive and systemic expression of(More)
Genome stability is regulated by the balance between efficiencies of the repair machinery and genetic alterations such as mutations and chromosomal rearrangements. It has been postulated that deregulation of class switch recombination (CSR) and somatic hypermutation (SHM), which modify the immunoglobulin (Ig) genes in activated B cells, may be responsible(More)