Vincenzo Constanzo: Molecular Mechanisms of  Replication Fork Protection

29. 3. 2018, University Campus Bohunice

About the lecture

Maintenance of genome integrity during DNA replication relies on several other factors that do not directly participate in DNA synthesis. Among these there are proteins that are important to respond to DNA lesions and structures impairing replication fork progression.

These factors are believed to be particularly important for replication of specific chromosome regions with complex or repetitive DNA sequence composition. In my group, we combine the use of biochemical analysis based on the Xenopus egg extract with advanced imaging techniques based on transmission electron microscopy (EM) to visualize replication intermediates obtained from genomic DNA replicated in extracts depleted of essential DNA metabolism proteins.

This approach allowed us to uncover for the first time a major role for RAD51 in preventing Mre11 mediated processing of nascent synthesized DNA behind replication forks (Hashimoto et al 2010, NSMB).

More recently, we have shown that extensive DNA degradation is triggered by the formation of reversed forks at stalled forks operated by SNF2 helicases (Kolinjivadi et al 2017, Mol Cell). These pathways are likely to play a major role at repetitive DNA, including the centromeres, which we have shown to be enriched for DNA repair factors (Aze et al 2016, NCB). This work will be discussed in light of recent results obtained on replication fork protection mechanisms.

Dr. Vincenzo Costanzo

IFOM - Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy

  • He directs the DNA metabolism research program at IFOM.
  • He identified for the first time two new roles for the main repair protein RAD51, which is directly controlled by the BRCA2 protein. Mutations in the BRCA2 gene are associated with Hereditary Breast-Ovarian Cancer Syndrome, and have been implicated recently also in many other tumors.
  • Costanzo’s work showed for the first time that RAD51 is essential to protect nascent DNA from nuclease mediated degradation at normal and stalled replication forks and that it is required to promote continuous DNA replication. 
  • He worked closely with Tim Hunt, recipient of a Nobel Prize in 2001 for cell cycle research, with whom he published important studies on the control of DNA replication.
  • He also collaborated with Tomas Lindalh Nobel Prize recipient in 2015 for his discoveries on DNA repair He won several awards, including the prestigious Lister Prize for Preventive Medicine and the European Research Council (ERC) grant for junior investigators.
  • In 2013, thanks also to the contribution of the Harvard-Armenise Foundantion and the award of a second ERC consolidator grant he returned to Italy and started the DNA Metabolism research program at IFOM. 
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