Branchpoint translocation by fork remodelers as a general mechanism of R-loop removal.

Co-transcriptional R loops arise from stalling of RNA polymerase, leading to the formation of stable DNA:RNA hybrids. Unresolved R loops promote genome instability but are counteracted by helicases and nucleases. Here, we show that branchpoint translocases are a third class of R-loop-displacing enzyme in vitro. In cells, deficiency in the Fanconi-anemia-associated branchpoint translocase FANCM causes R-loop accumulation, particularly after treatment with DNA:RNA-hybrid-stabilizing agents. This correlates with FANCM localization at R-loop-prone regions of the genome. Moreover, other branchpoint translocases associated with human disease, such as SMARCAL1 and ZRANB3, and those from lower organisms can also remove R loops in vitro. Branchpoint translocases are more potent than helicases in resolving R loops, indicating their evolutionary important role in R-loop suppression. In human cells, FANCM, SMARCAL1, and ZRANB3 depletion causes additive effects on R-loop accumulation and DNA damage. Our work reveals a mechanistic basis for R-loop displacement that is linked to genome stability

Bispectral index monitoring during cardiopulmonary resuscitation repeated twice within 8 days in the same patient: a case report

Research on cardiac resuscitation has led to various changes in the techniques and drug administration involved in modern advanced life support. Besides improving primary cardiac survival, interest is increasingly focused on a favourable neurological outcome. However, until now there has been no on-site equipment to support the clinical observations of the cardiopulmonary resuscitation (CPR) team. Bispectral index (BIS) monitoring has been used for avoiding awareness during anaesthesia for many years. We report a case of a 68-year-old patient suffering twice from cardiac arrest due to thromboembolism within a few days. While the first cardiac resuscitation was survived without neurological consequences, the patient died after the second event. Both resuscitation events were monitored using the BIS. We discuss the course of BIS values and their possible contribution to the prediction of outcome

The Anglo-Saxon migration and the formation of the early English gene pool

The history of the British Isles and Ireland is characterized by multiple periods of major cultural change, including the influential transformation after the end of Roman rule, which precipitated shifts in language, settlement patterns and material culture1. The extent to which migration from continental Europe mediated these transitions is a matter of long-standing debate2–4. Here we study genome-wide ancient DNA from 460 medieval northwestern Europeans—including 278 individuals from England—alongside archaeological data, to infer contemporary population dynamics. We identify a substantial increase of continental northern European ancestry in early medieval England, which is closely related to the early medieval and present-day inhabitants of Germany and Denmark, implying large-scale substantial migration across the North Sea into Britain during the Early Middle Ages. As a result, the individuals who we analysed from eastern England derived up to 76% of their ancestry from the continental North Sea zone, albeit with substantial regional variation and heterogeneity within sites. We show that women with immigrant ancestry were more often furnished with grave goods than women with local ancestry, whereas men with weapons were as likely not to be of immigrant ancestry. A comparison with present- day Britain indicates that subsequent demographic events reduced the fraction of continental northern European ancestry while introducing further ancestry components into the English gene pool, including substantial southwestern European ancestry most closely related to that seen in Iron Age Franc

Ten millennia of hepatitis B virus evolution

Hepatitis B virus (HBV) has been infecting humans for millennia and remains a global health problem, but its past diversity and dispersal routes are largely unknown. We generated HBV genomic data from 137 Eurasians and Native Americans dated between similar to 10,500 and similar to 400 years ago. We date the most recent common ancestor of all HBV lineages to between similar to 20,000 and 12,000 years ago, with the virus present in European and South American hunter-gatherers during the early Holocene. After the European Neolithic transition, Mesolithic HBV strains were replaced by a lineage likely disseminated by early farmers that prevailed throughout western Eurasia for similar to 4000 years, declining around the end of the 2nd millennium BCE. The only remnant of this prehistoric HBV diversity is the rare genotype G, which appears to have reemerged during the HIV pandemic.Molecular Technology and Informatics for Personalised Medicine and Healt

Author Correction: The Anglo-Saxon migration and the formation of the early English gene pool.

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The Anglo-Saxon migration and the formation of the early English gene pool

The history of the British Isles and Ireland is characterized by multiple periods of major cultural change, including the influential transformation after the end of Roman rule, which precipitated shifts in language, settlement patterns and material culture1. The extent to which migration from continental Europe mediated these transitions is a matter of long-standing debate2,3,4. Here we study genome-wide ancient DNA from 460 medieval northwestern Europeans—including 278 individuals from England—alongside archaeological data, to infer contemporary population dynamics. We identify a substantial increase of continental northern European ancestry in early medieval England, which is closely related to the early medieval and present-day inhabitants of Germany and Denmark, implying large-scale substantial migration across the North Sea into Britain during the Early Middle Ages. As a result, the individuals who we analysed from eastern England derived up to 76% of their ancestry from the continental North Sea zone, albeit with substantial regional variation and heterogeneity within sites. We show that women with immigrant ancestry were more often furnished with grave goods than women with local ancestry, whereas men with weapons were as likely not to be of immigrant ancestry. A comparison with present-day Britain indicates that subsequent demographic events reduced the fraction of continental northern European ancestry while introducing further ancestry components into the English gene pool, including substantial southwestern European ancestry most closely related to that seen in Iron Age France5,6

ATR-Mediated FANCI Phosphorylation Regulates Both Ubiquitination and Deubiquitination of FANCD2

DNA interstrand crosslinks (ICLs) are a physical barrier to replication and therefore toxic to cell viability. An important mechanism for the removal of ICLs is the Fanconi Anemia DNA repair pathway, which is initiated by mono-ubiquitination of FANCD2 and its partner protein FANCI. Here, we show that maintenance of FANCD2 and FANCI proteins in a monoubiquitinated form is regulated by the ATR-kinase. Using recombinant proteins in biochemical reconstitution experiments we show that ATR directly phosphorylates FANCI on serine 556, 559, and 565 to stabilize its association with DNA and FANCD2. This increased association with DNA stimulates the conjugation of ubiquitin to both FANCI and FANCD2, but also inhibits ubiquitin deconjugation. Using phosphomimetic and phosphodead mutants of FANCI we show that S559 and S565 are particularly important for protecting the complex from the activity of the deubiquitinating enzyme USP1:UAF1. Our results reveal a major mechanism by which ATR kinase maintains the activation of the FA pathway, by promoting the accumulation of FANCD2 in the ubiquitinated form active in DNA repair

Methodology for the identification of small molecule inhibitors of the Fanconi Anaemia ubiquitin E3 ligase complex

DNA inter-strand crosslinks (ICLs) threaten genomic stability by creating a physical barrier to DNA replication and transcription. ICLs can be caused by endogenous reactive metabolites or from chemotherapeutics. ICL repair in humans depends heavily on the Fanconi Anaemia (FA) pathway. A key signalling step of the FA pathway is the mono-ubiquitination of Fanconi Anaemia Complementation Group D2 (FANCD2), which is achieved by the multi-subunit E3 ligase complex. FANCD2 mono-ubiquitination leads to the recruitment of DNA repair proteins to the site of the ICL. The loss of FANCD2 mono-ubiquitination is a common clinical feature of FA patient cells. Therefore, molecules that restore FANCD2 mono-ubiquitination could lead to a potential drug for the management of FA. On the other hand, in some cancers, FANCD2 mono-ubiquitination has been shown to be essential for cell survival. Therefore, inhibition of FANCD2 mono-ubiquitination represents a possible therapeutic strategy for cancer specific killing. We transferred an 11-protein FANCD2 mono-ubiquitination assay to a high-throughput format. We screened 9,067 compounds for both activation and inhibition of the E3 ligase complex. The use of orthogonal assays revealed that candidate compounds acted via non-specific mechanisms. However, our high-throughput biochemical assays demonstrate the feasibility of using sophisticated and robust biochemistry to screen for small molecules that modulate a key step in the FA pathway. The future identification of FA pathway modulators is anticipated to guide future medicinal chemistry projects with drug leads for human disease