The histone H3 variant CenH3, called CENP-A in humans, is central in centromeric chromatin to ensure proper chromosome segregation. In the absence of an underlying DNA sequence, it is still unclear how CENP-A deposition at centromeres is determined. Here, we purified non-nucleosomal CENP-A complexes to identify direct CENP-A partners involved in such a mechanism and identified HJURP. HJURP was not detected in H3.1- or H3.3-containing complexes, indicating its specificity for CENP-A. HJURP centromeric localization is cell cycle regulated, and its transient appearance at the centromere coincides precisely with the proposed time window for new CENP-A deposition. Furthermore, HJURP downregulation leads to a major reduction in CENP-A at centromeres and impairs deposition of newly synthesized CENP-A, causing mitotic defects. We conclude that HJURP is a key factor for CENP-A deposition and maintenance at centromeres.

The Wnt signaling pathway is essential for development and organogenesis. Wnt signaling stabilizes beta-catenin, which accumulates in the cytoplasm, binds to 1-cell factor (TCF; also known as lymphocyte enhancer-binding factor, LEF) and then upregulates downstream genes. Mutations in CTNNB1 (encoding beta-catenin) or APC (adenomatous polyposis coli) have been reported in human neoplasms including colon cancers and hepatocellular carcinomas (HCCs). Because HCC5 tend to show accumulation of beta-catenin more often than mutations in CTNNB1, we looked for mutations in AXIN1, encoding a key factor for Wnt signaling, in 6 HCC cell lines and 100 primary HCC5. Among the 4 cell lines and 87 HCC5 in which we did not detect CTNNB1 mutations, we identified AXIN1 mutations in 3 cell lines and 6 mutations in 5 of the primary HCCs. In cell lines containing mutations in either gene, we observed increased DNA binding of TCF associated with beta-catenin in nuclei. Adenovirus mediated gene transfer of wild-type AXINI induced apoptosis in hepatocellular and colorectal cancer cells that had accumulated beta-catenin as a consequence of either APC, CTNNB1 or AXIN1 mutation, suggesting that axin may be an effective therapeutic molecule for suppressing growth of hepatocellular and colorectal cancers.

Chronic hepatitis B is a serious infectious liver disease that often progresses to liver cirrhosis and hepatocellular carcinoma; however, clinical outcomes after viral exposure vary enormously among individuals. Through a two-stage genome-wide association study using 786 Japanese chronic hepatitis B cases and 2,201 controls, we identified a significant association of chronic hepatitis B with 11 SNPs in a region including HLA-DPA1 and HLA-DPB1. We validated these associations by genotyping two SNPs from the region in three additional Japanese and Thai cohorts consisting of 1,300 cases and 2,100 controls (combined P = 6.34 x 10(-39) and 2.31 x 10(-38), OR = 0.57 and 0.56, respectively). Subsequent analyses revealed risk haplotypes (HLA-DPA1(*)0202-DPB1(*)0501 and HLA-DPA1(*)0202-DPB1(*)0301, OR = 1.45 and 2.31, respectively) and protective haplotypes (HLA-DPA1(*)0103-DPB1(*)0402 and HLA-DPA1(*)0103-DPB1(*)0401, OR = 0.52 and 0.57, respectively). Our findings show that genetic variants in the HLA-DP locus are strongly associated with risk of persistent infection with hepatitis B virus.

We report genome-wide association studies for hematological and biochemical traits from approximately 14,700 Japanese individuals. We identified 60 associations for 8 hematological traits and 29 associations for 12 biochemical traits at genome-wide significance levels (P < 5 x 10(-8)). Of these, 46 associations were new to this study and 43 replicated previous reports. We compared these associated loci with those reported in similar GWAS in European populations. When the minor allele frequency was >10% in the Japanese population, 32 (94.1%) and 31 (91.2%) of the 34 hematological loci previously reported to be associated in a European population were replicated with P-values less than 0.05 and 0.01, respectively, and 31 (73.8%) and 27 (64.3%) of the 42 European biochemical loci were replicated.

The EP300 protein is a histone acetyltransferase that regulates transcription via chromatin remodelling and is important in the processes of cell proliferation and differentiation. EP300 acetylation of TP53 in response to DNA damage regulates its DNA-binding and transcription functions. A role for EP300 in cancer has been implied by the fact that it is targeted by viral oncoproteins, it is fused to MLL in Leukaemia and two missense sequence alterations in EP300 were identified in epithelial malignancies. Nevertheless, direct demonstration of the role of EP300 in tumorigenesis by inactivating mutations in human cancers has been lacking. Here we describe EP300 mutations, which predict a truncated protein, in 6(3%) of 193 epithelial cancers analysed. Of these six mutations, two were in primary tumours (a colorectal cancer and a breast cancer) and four were in cancer cell lines (colorectal, breast and pancreatic). In addition, we identified a somatic in-frame insertion in a primary breast cancer and missense alterations in a primary colorectal cancer and two cell lines (breast and pancreatic). Inactivation of the second allele was demonstrated in five of six cases with truncating mutations and in two other cases. Our data show that EP300 is mutated in epithelial cancers and provide the first evidence that it behaves as a classical tumour-suppressor gene.