H2020Индивидуална стипендия2020–2022

HollidayTrack · Tracking the movement and dynamics of Holliday junctions

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2020-04-01 → 2022-03-31
Финансиране от ЕС: 212 934 €
Участници: 1
Схема: MSCA-IF

Линиите свързват координатора с партньорите.

Накратко на български

Движението на т.нар. „Х олидей junctions“ – специални връзки между две нишки ДНК при тяхното възстановяване – се проучва в живи клетки. Разбирането на този процес помага да се разбере как се предотвратяват генетични грешки и развитието на рак.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Tracking the movement and dynamics of Holliday junctions

Our cells are continually challenged by various kinds of DNA damage, which needs to be repaired to avoid loss of genetic information, genomic instability and to prevent cancer development. The most toxic type of DNA damage are DNA double strand breaks (DSBs). Therefore, our cells have developed elaborate DNA repair mechanism to ensure genomic integrity. DSBs can be repaired via two major pathways, non-homologous end joining (NHEJ) or homologous recombination (HR). Whilst NHEJ fuses broken DNA ends and is potentially ‘error prone’, HR is considered to be an ‘error-free’ mechanism of DSB repair. HR occurs between homologous DNA sequences that are provided by the undamaged sister chromatid and can lead to the formation of Holliday junctions (HJs) that covalently link sister chromatids. HJs are mobile and can migrate through homologous sequences, a phenomenon called branch migration. These movements can occur spontaneously or can be enzymatically driven by a DNA translocase or helicase. To date, branch migration has only been studied in vitro due to the lack of tools to detect HJs in cells. In a cell, HJs must be resolved to allow sister chromatid separation in mitosis. Depending on the processing of the HJ. In humans, two pathways are known to separate the recombining DNA molecules: the first is known as ‘dissolution’ and involves BLM, Topoisomerase III, RMI1 and RMI2 (BTRR). The second pathway is termed ‘resolution’ and involves structure-selective endonucleases that cleave HJs. Two structure selective endonucleases are responsible for HJ resolution in human cells: GEN1 and the SMX complex (SLX1-SLX4-MUS81-EME1-XPF-ERCC1). Defects in dissolution are observed as an increased frequency of sister chromatid exchanges, whereas resolvase-deficient cells in combination with BLM mutations are inviable. There are several outstanding questions regarding the in vivo properties of HJ intermediates that I intend to answer: 1) How far do HJs branch migrate from the site of DSB formation? 2) What enzymes drive HJ branch migration in vivo? 3) How do HJ processing enzymes influence the HJs branch migration?

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

omologous recombination (HR) is a DNA repair pathway that plays a central role in the maintenance of genomic stability and cancer prevention. In the late stages of HR, recombination intermediates (Holliday junctions, HJs) need to be resolved to allow proper chromosome segregation. Whilst HJ processing reactions have been well characterised in vitro, there is limited knowledge of the dynamic properties of these structures within a cellular context. To explore the biological properties of HJs in vivo, I will use site-specific DNA cleavage and ChIP-sequencing techniques to reveal the distance of HJ migration from the site where HR is initiated. The ability of HJs to branch migrate spontaneously or be driven by potential HJ translocases will be determined using RAD54, BLM, WRN, RECQ1, RECQ5 and FANCM deficient cells. To enable these studies, my first challenge will be to develop a molecular tool that specifically detects HJs in vivo, that can be used to monitor the appearance and kinetics of HJs after DNA double strand break formation. The specific DNA break sites and corresponding HJ migration will be determined with respect to the dynamic chromosome domain architecture and organisation within human cells, which will provide valuable insights into the impact of local chromatin structure on HJ migration and resolution. Additionally, the newly developed HJ-specific tools may be applied to ask a wide range of questions relating to the role of HJs in telomere biology and replication fork reversal or to study patterns and distributions of HJ formation and migration in different cancer cell types.

Оригинален текст от CORDIS (на английски).

Участници

THE FRANCIS CRICK INSTITUTE LIMITED · LondonКоординаторОбединеното кралство