Cockayne syndrome and oxidative damage



Cockayne syndrome and oxidative damage


Barbara Pascucci
Giorgio Pochetti
Roberta Montanari


Cockayne syndrome, oxidative stress, metabolic dysfunction, proteins interactions

Istituto Superiore di Sanità
Istituto di Genetica Molecolare, CNR Pavia
Gray Institute for Radiation Oncology & Biology, University of Oxford.

Cockayne syndrome (CS) is a rare inherited disorder categorized as a segmental progeroid disorder. The cardinal clinical features of CS are pre- or post-natal growth failure, leading to a characteristic appearance of so-called cachectic dwarfism, progressive neurological dysfunction and precocious aging. The two genes identified so far as responsible for CS, CSA and CSB, are key players in nucleotide excision repair (NER) of transcribed sequences of active genes (transcription coupled repair, TCR). A growing body of evidence indicates that CS proteins are directly involved in base excision repair (BER) that is the major pathway responsible for oxidation/alkylation DNA damage repair (D'Errico et al. 2007, Oncogene).
To investigate whether CS proteins play a role within the BER pathway, a cross-linking assay will be used to monitor the real-time engagement of BER proteins in extracts form CS cells as compared to WT cells. The analysis of CS associated protein complexes at oxidized damaged sites will be performed by a chromatin-binding assay and by co-immunoprecipitation experiments. A deeply characterization of the molecular defects of CS syndrome will be performed by measuring ROS activity, valutating DNA repair capacity and analysing the metabolic fingerprints by nuclear magnetic resonance (NMR). Preliminary results show that the metabolic fingerprints reveal perturbed oxidative metabolism and mitochondrial dysfunction that are associated with a remarkable increase of intracellular ROS levels. Moreover, we show a direct involvement of CSA and CSB in the processing of BER intermediates. These data taken together indicate a role of CSA and CSB in the control of oxidative metabolism and in the processing of DNA single strand breaks (SSB) and offer a clue for the clinical outcome of CS. The approach of NMR could give access to important indicators of accumulation of DNA damage and response to treatment, provide novel bio-imaging markers, and allow new ways of monitoring the effects of targeted therapies for these premature aging syndromes. Finally, structural studies of WT and mutated proteins are in progress in order to better understand the molecular defects of this syndrome.



Barbara Pascucci
Tel.: 0690672631 or 0649902560


Last Updated (Tuesday, 21 December 2010 16:58)