Luedtke, N. W. | bioRxiv Science

bioRxiv2024

Spatiotemporal visualization of DNA replication by click chemistry reveals bubbling of viral DNA in virion formation

The organisation of human chromosomes reversibly changes in cell division, and irreversibly in apoptosis or erythropoiesis by DNA condensation and fragmentation processes. Yet, how viral replication in the nucleus affects host and viral chromatin organisation remains poorly understood. Here we used dual-color click chemistry to image human adenovirus DNA replication, demonstrating host chromatin compaction during active expansion of the viral replication compartment (VRC). Early-replicated viral DNA (vDNA) segregated from VRC and lost phospho-serine5-RNA Pol-II and viral DNA-binding protein (DBP), while late-replicated vDNA retained active RNA Pol-II, besides viral RNA-splicing and DNA-packaging proteins. Depending on replication and the assembly protein 52K, the late-stage VRCs gave rise to progeny by droplet formation of vDNA with GFP-tagged virion protein V into 52K biomolecular condensates. The study reveals distinct functions of early and late-replicated vDNA and provides insight into active and passive liquid phase separated zones conducive to selective genome packaging of nascent virions.

microbiology↗

bioRxiv2021

Cancer Prognosis According to Parthanatos Features

For nearly 50 years, translational research studies aimed at improving chemotherapy-induced killing of cancer cells have focused on the induction of apoptosis. Here we show that a PARP-1-mediated programmed cell death mechanism "parthanatos" is associated with the successful, front-line treatment of a common cancer. Peripheral blood mononuclear cells (PBMCs) from healthy human donors (10 of 10 tested), as well as primary cancer cells from approximately 50% of acute myeloid leukemia (AML) patients (n = 18 of 39 tested, French-American-British (FAB) subtypes M4 and M5) exhibited two distinctive features of parthanatos upon treatment with a front-line drug combination of cytarabine and an anthracycline. Statistically significant improvements in survival rates were observed in the parthanatos positive versus parthanatos negative AML patient groups (HR = 0.22 - 0.38, p = 0.002 - 0.05). Near-median expression of PARP1 mRNA was associated with a 50% longer survival time (HR = 0.66, p = 0.01), and the poly [ADP-ribose] polymerase (PARP) inhibitor Olaparib exhibited antagonistic activities against ara-C and idarubicin in primary blood monocytes from healthy donors as well as primary cancer isolates from ~50% of AML patients. Together these results suggest that PARP activity is a prognostic biomarker for AML subtypes M4 and M5 and support the relevance of parthanatos in curative chemotherapy of AML. In BriefMessikommer and co-workers report that PARP-1-mediated programmed cell death is associated with successful, front-line treatment of acute myeloid leukemia (AML). HighlightsO_LIThe first-line cancer drug cytarabine (ara-C) induces parthanatos or apoptosis, depending on the specific AML cell line being treated. C_LIO_LIOCI-AML3 cells undergo parthanatos or apoptosis, depending on the specific drug being added. C_LIO_LIThe presence of two parthanatos features in primary cancer cells from AML patients (n = 18 of 39 tested) having French-American-British (FAB) subclassifications M4 or M5 is associated with four-fold improved survival (HR = 0.23, p = 0.01) following curative chemotherapy with ara-C and an anthracycline. C_LIO_LIThe poly [ADP-ribose] polymerase (PARP) inhibitor Olaparib exhibits antagonistic activities against ara-C and idarubicin in primary blood monocytes from healthy donors as well as primary cancer isolates from ~50% of AML patients. C_LIO_LINear-median expression of PARP1 mRNA is associated with a 50% increase in survival time (HR = 0.66, p = 0.01) of AML patients following chemotherapy with ara-C and idarubicin. C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=118 HEIGHT=200 SRC="FIGDIR/small/445484v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@af2a33org.highwire.dtl.DTLVardef@1fb8e1corg.highwire.dtl.DTLVardef@2eebf4org.highwire.dtl.DTLVardef@84eb8c_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗