Forsøksdyr: Characterization of NHEJ null mice after experimental hypoxic-ischemic brain damage and behavior studies

Godkjenningsdato 11.12.2018

Godkjenningsperiode 12.12.2018-11.12.2022

Mammalian cells repair DNA double-strand breaks (DSBs) by the Non-homologous DNA end-joining (NHEJ) pathway. NHEJ includes four core factors, Ku70 and Ku80 effectors, scaffold protein XRCC4 and a ligase subunit DNA ligase 4. In addition, there are accessory factors such as XLF, PAXX, Cyren and proteine kinase DNA-PKcs. Inactivation of Ku70, Ku80, XRCC4 or Ligase 4 leads to massive neuronal apoptosis and immunodeficiency in mice. Much less is known about the function of XLF, PAXX and Cyren/Mri.

To elucidate the function of XLF, PAXX and Cyren in vivo, murine models were generated. By date, its is known that XLF, PAXX and Cyren has functional redundancy with several DNA damage response proteins, including ATM, H2AX, 53BP1 and DNA-PKcs. However, further details are necessary to determine specific processes explaining function of XLF in DNA repair and its impact on health.

The goal of this study is to analyze the biological significance of XLF, PAXX and Cyren for neuroprotection in brain using XLF, PAXX and Cyren deficient mouse models.

We expect that the results from these experiments will reveal new drug targets for treatment of neurodegenerative disease and brain tumor.

Total number of mice for experiments with all three strains (XLF, PAXX and Cyrin) and wt: 2070+1590 = 3660.

Cell cultures will be used for experiments in which we don't need to use the whole animal. However, we also aim to analyse whole organs and examine the behavior of the KO mice. For these kind of experiments we need a whole organism which is comparable to humans, and mouse is a suitable model organism.

All the methods described are well established in our lab, we are therefore able to keep the number of animals used to a minimum. We will use the same animals in different experiments, e.g. the same animals for all the three different behavior tests and aging mice.

The hypoxia ischemia (HI) experiments starts early in the morning and thus allows time for observation of the pups in the afternoon, any sign of pain or discomfort will be evaluated frequently during and after HI-experiments.