When a cut makes the difference : DNA damage incision from human cells to C. elegans

The DNA damage response (DDR) is a complex network of DNA repair processes and associated signaling mechanisms that maintains genome integrity by removing DNA lesions that are continuously induced by endogenous and exogenous sources. The intricate cooperation of all DNA repair and signaling mechanisms involved in the DDR determines how cells cope with DNA damage. In this thesis, particular attention is given to two major DNA repair pathways: the first is nucleotide excision repair (NER), which removes DNA-helix distorting lesions such as those induced by UV light. The second is interstrand crosslink repair (ICLR), which removes covalent linkages between bases on opposing DNA strands induced by DNA crosslinking chemicals and antitumor agents, such as cisplatin, psoralens and mitomycin C. The structure specific endonuclease ERCC1-XPF is essential to incise DNA next to lesions during both NER and ICLR. In humans, mutations in this complex give rise to hereditary DNA repair syndromes such as xeroderma pigmentosum (XP), Cockayne syndrome (CS), xeroderma pigmentosum-Cockayne syndrome complex (XPCS), and Fanconi anemia (FA). Most of the XPF patients carry heterozygous mutations, which makes it difficult to dissect the link between each XPF allele and its phenotypic consequences. Here, we investigate how XPF mutations reported in XP and XPCS patients functionally affect XPF activity in NER. By means of confocal imaging, genetic and proteomics approaches on human cells in culture we show that XP-causing mutations diminish XPF recruitment to DNA damage and only mildly affect repair capacity. In contrast, XPCS-causing mutation impair repair capacity, and are associated with persistent binding or continuous recruitment of XPF and the core NER machinery to UV-induced DNA damage. Moreover, our results suggest that different patient phenotypes associated with XPF mutations are dependent on the ability of the other XPF allele to function in NER. While it is well known that engagement of ERCC1-XPF in NER is facilitated by binding to the key factor XPA, how its recruitment in ICLR is regulated is less clear. Therefore, we investigated how in h

ERCC1–XPF targeting to psoralen–DNA crosslinks depends on XPA and FANCD2

The effectiveness of many DNA-damaging chemotherapeutic drugs depends on their ability to form monoadducts, intrastrand crosslinks and/or interstrand crosslinks (ICLs) that interfere with transcription and replication. The ERCC1–XPF endonuclease plays a critical role in removal of these lesions by incising DNA either as part of nucleotide excision repair (NER) or interstrand crosslink repair (ICLR). Engagement of ERCC1–XPF in NER is well characterized and is facilitated by binding to the XPA protein. However, ERCC1–XPF recruitment to ICLs is less well u

Tissue-Specific DNA Repair Activity of ERCC-1/XPF-1

Sabatella et al. image the DNA repair endonuclease ERCC-1/XPF-1 in C. elegans to show that nucleotide excision repair exhibits tissue-specific activity. DNA lesions are very rapidly removed from the entire genome in oocytes but only from transcribed genes in somatic cells. Neurons are more sensitive to DNA damage than muscle cells.Hereditary DNA repair defects affect tissues differently, suggesting that in vivo cells respond differently to DNA damage. Knowledge of the DNA damage response, however, is largely based on in vitro and cell culture studies, and it is currently unclear whether DNA repair changes depending on the cell type. Here, we use in vivo imaging of the nucleotide excision repair (NER) endonuclease ERCC-1/XPF-1 in C. elegans to demonstrate tissue-specific NER activit

Report of the 12th Liaison Meeting

The 12th Liaison meeting was held in Brussels on 8th and 9th October 2015 to address the following Terms of Reference: TOR 1. Discussion on possible follow-­‐‑up to the main outputs/recommendations of: • The 2015 RCMs -­‐‑ specific recommendations addressed to the Liaison Meeting • PGECON, PGDATA, PGMed – outcomes and recommendations from their 2015 meeting • STECF EWG and STECF Plenary -­‐‑ outcomes and recommendations from their 2015 meetings • Data end users (ICES, STECF, RFMOs – GFCM, IATTC, ICCAT, IOTC, WCPFC, NAFO, SPRFMO, CECAF, WECAFC) TOR2. End user feedback on data transmission and related issues • Discuss feedback received from data end-­‐‑users on data transmission: main issues and possible harmonization of end user feedback to the Commission • JRC data transmission IT platform: experience gained and future steps • Discuss best practices on automatization of data upload by MS: data validation tools used by end users • Discussion on new set-­‐‑up for STECF evaluation of AR2014 & data transmission 2014 used in 2015 – continue like this next year? • Harmonisation and dissemination of DCF metadata: codelists, metiers, nomenclatures, best practices, standards • RCM data calls – overview of how MS responded TOR 3. Regional cooperation • Call for proposals MARE/2014/19 'ʹStrengthening Regional Cooperation in the area of fisheries data collection– state of play'ʹ. Presentation by a representative of the two RCG grants and discussions by LM thereafter. What should be the way forward? • Regional databases • Overview of use of the Regional Databases for RCMs in 2015 and problems identified • Other developments (RDB trainings in 2015, RDB Med&BS development) • Changes for the future – any recommendations from the LM? • Future role of RCMs and DCF-­‐‑related meetings: best practices, coordination, cohesion and common structure in line with emerging needs of DCF TOR 4. EU MAP • Discuss recommendations/ output of RCMs: List of proposed stocks, landing obligation, metiers • Discuss design-­‐‑based sampling in relation to DCF: does it fulfil DCF requirements? TOR 5. Availability of data • Overview of latest developments (DCF Database Feasibility Study and plans for a follow-­‐‑up study to this) TOR 6. AOB • Agree on a list of recommendations relating to DCF (that MS will need to report on in their AR2015) – COM will provide a compilation of proposed recommendations from LM & STECF Plenaries in 2014 as input • Prepare a list of recommended meetings for 2016 as guidance for MS • Review and prioritize DCF-­‐‑related study proposals from RCMs, PGECON, EGs etc • ICES update on workshop on concurrent sampling and plans to re-­‐‑evaluate survey

Neuropeptide signaling regulates the susceptibility of developing C. elegans to anoxia

Inadequate delivery of oxygen to organisms during development can lead to cell dysfunction/death and life-long disabilities. Although the susceptibility of developing cells to low oxygen conditions changes with maturation, the cellular and molecular pathways that govern responses to low oxygen are incompletely understood. Here we show that developing Caenorhabditis elegans are substantially more sensitive to anoxia than adult animals and that this sensitivity is controlled by nervous system generated hormones (e.g., neuropeptides). A screen of neuropeptide genes identified and validated nlp-40 and its receptor aex-2 as a key regulator of anoxic survival in developing worms. The survival-promoting action of impaired neuropeptide signaling does not rely on five known stress resistance pathways and is specific to anoxic insult. Together, these data highlight a novel cell non-autonomous pathway that regulates the susceptibility of developing organisms to anoxia

Base and nucleotide excision repair facilitate resolution of platinum drugs-induced transcription blockage

Sensitivity and resistance of cells to platinum drug chemotherapy are to a large extent determined by activity of the DNA damage response (DDR). Combining chemotherapy with inhibition of specific DDR pathways could therefore improve treatment efficacy. Multiple DDR pathways have been implicated in removal of platinum-DNA lesions, but it is unclear which exact pathways are most important to cellular platinum drug resistance. Here, we used CRISPR/Cas9 screening to identify DDR proteins that protect colorectal cancer cells against the clinically applied platinum drug oxaliplatin. We find that besides the expected homologous recombination, Fanconi anemia and translesion synthesis pathways, in particular also transcription-coupled nucleotide excision repair (TC-NER) and base excision repair (BER) protect against platinum-induced cytotoxicity. Both repair pathways are required to overcome oxaliplatin- and cisplatin-induced transcription arrest. In addition to the generation of DNA crosslinks, exposure to platinum drugs leads to reactive oxygen species production that induces oxidative DNA lesions, explaining the requirement for BER. Our findings highlight the importance of transcriptional integrity in cells exposed to platinum drugs and suggest that both TC-NER and BER should be considered as targets for novel combinatorial treatment strategies

Repair protein persistence at DNA lesions characterizes XPF defect with Cockayne syndrome features

The structure-specific ERCC1-XPF endonuclease plays a key role in DNA damage excision by nucleotide excision repair (NER) and interstrand crosslink repair. Mutations in this complex can either cause xeroderma pigmentosum (XP) or XP combined with Cockayne syndrome (XPCS-complex) or Fanconi anemia. However, most patients carry compound heterozygous mutations, which confounds the dissection of the phenotypic consequences for each of the identified XPF alleles. Here, we analyzed the functional impact of individual pathogenic XPF alleles on NER. We show that XP-causing mutations diminish XPF recruitment to DNA damage and only mildly affect global genome NER. In contrast, an XPCS-complex-specific mutation causes persistent recruitment of XPF and the upstream core NER machinery to DNA damage and severely impairs both global genome and transcription-coupled NER. Remarkably, persistence of NER factors at DNA damage appears to be a common feature of XPCS-complex cells, suggesting that this could be a determining factor contributing to the development of additional developmental and/or neurodegenerative features in XP patients

STECF Fisheries Dependent Information – FDI (STECF-19-11)

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. The STECF reviewed the report of the EWG on Fisheries-dependent Information during its winter 2019 plenary meeting

Simulating the Effects of Alternative Management Measures of Trawl Fisheries in the Central Mediterranean Sea: Application of a Multi-Species Bio-economic Modeling Approach

In the last decades, the Mediterranean Sea experienced an increasing trend of fish stocks in overfishing status. Therefore, management actions to achieve a more sustainable exploitation of fishery resources are required and compelling. In this study, a spatially explicit multi-species bio-economic modeling approach, namely, SMART, was applied to the case study of central Mediterranean Sea to assess the potential effects of different trawl fisheries management scenarios on the demersal resources. The approach combines multiple modeling components, integrating the best available sets of spatial data about catches and stocks, fishing footprint from vessel monitoring systems (VMS) and economic parameters in order to describe the relationships between fishing effort pattern and impacts on resources and socio-economic consequences. Moreover, SMART takes into account the bi-directional connectivity between spawning and nurseries areas of target species, embedding the outcomes of a larvae transport Lagrangian model and of an empirical model of fish migration. Finally, population dynamics and trophic relationships are considered using a MICE (Models of Intermediate Complexity) approach. SMART simulates the fishing effort reallocation resulting from the introduction of different management scenarios. Specifically, SMART was applied to evaluate the potential benefits of different management approaches of the trawl fisheries targeting demersal stocks (deepwater rose shrimp Parapenaeus longirostris, the giant red shrimp Aristaeomorpha foliacea, the European hake Merluccius merluccius, and the red mullet Mullus barbatus) in the Strait of Sicily. The simulated management scenarios included a reduction of both fishing capacity and effort, two different sets of temporal fishing closures, and two sets of spatial fishing closures, defined involving fishers. Results showed that both temporal and spatial closures are expected to determine a significant improvement in the exploitation pattern for all the species, ultimately leading to the substantial recovery of spawning stock biomass for the stocks. Overall, one of the management scenarios suggested by fishers scored better and confirms the usefulness of participatory approaches, suggesting the need for more public consultation when dealing with resource management at sea