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PolyADP-ribosylation (PARylation) is a posttranslational modification that is involved in the various cellular functions including DNA repair, genomic stability, and transcriptional regulation. PARylation is catalyzed by the poly(ADP-ribose) polymerase (PARP) family proteins, which mainly recognize damaged DNA and initiate repair processes. PARP inhibitors are expected to be novel anticancer drugs for breast and ovarian cancers having mutation in BRCA tumor suppressor genes. However the structure of intact (full-length) PARP is not yet known. We have produced and purified the full-length human PARP1 (h-PARP1), which is the major family member of PARPs, and analyzed it with single particle electron microscopy. The electron microscopic images and the reconstructed 3D density map revealed a dimeric configuration of the h-PARP1, in which two ring-shaped subunits are associated with two-fold symmetry. Although the PARP1 is hypothesized to form a dimer on damaged DNA, the quaternary structure of this protein is still controversial. The present result would provide the first structural evidence of the dimeric structure of PARP1. [ABSTRACT FROM AUTHOR]

Glycoform of mucin 1 (MUC1) in cancerous cells changes markedly with cell differentiation, and thus, qualitative detection and verification of the MUC1 glycosylation changes have potential diagnostic value. We have developed an ultrasensitive method to detect the changes in cholangiocarcinoma (CC), which produces MUC1, and applied it in the diagnostics development. The focused glycan analysis using 43-lectin-immobilized microarray could obtain the glycan profiles of sialylated MUC1 in 5 μL of sera. The high-throughput analysis detected disease-specific alterations of glycosylation, and the statistical analysis confirmed that use of Wisteria floribunda agglutinin (WFA) alone produced a diagnostic score sufficient for discriminating 33 CC cases from 40 hepatolithiasis patients and 48 normal controls (p < 0.0001). The CC-related glycosylation change was verified by the lectin-antibody sandwich ELISA with WFA in two cohorts: (1) 78 Opisthorchis viverrini infected patients without CC and 78 with CC, (2) 33 CC patients and 40 hepatolithiasis patients (the same cohort used for the above lectin microarray). The WFA positivity distinguished patients with CC (opisthorchiasis: p < 0.0001, odds ratio = 1.047; hepatolithiasis: p = 0.0002, odds ratio = 1.018). Sensitive detection of qualitative alterations of sialylated MUC1 glycosylation is indispensable for the development of our glycodiagnostic test for CC. [ABSTRACT FROM AUTHOR]