The cerebellum is exquisitely sensitive to deficiencies in the cellular response to specific DNA lesions. Genetic disorders caused by such deficiencies involve relentless, progressive cerebellar atrophy with striking loss of Purkinje and granule neurons. The reason for the extreme sensitivity of these cells to defective response to certain DNA lesions is unclear. This is particularly true for ataxia-telangiectasia (A-T) - a genomic instability syndrome whose major symptom is cerebellar atrophy. It is important to understand whether the DNA damage response in the cerebellum, particularly in Purkinje neurons, has special characteristics that stem from the unique features of these cells. Murine cerebellar organotypic cultures provide a valuable experimental system for this purpose since they retain the tissue organization for several weeks in culture and appear to provide the delicate Purkinje neurons with a physiological environment close to that in vivo. We have optimized this system and are using it to examine the Atm-mediated DNA damage response (DDR) in the cerebellum, with special emphasis on Purkinje cells. Our results to date, which indicate special chromatin organization in Purkinje cells that affects certain pathways of the DDR, demonstrate the usefulness of cerebellar organotypic cultures for addressing the above questions.
Keywords: 53BP1; A-T; A-TLD; AOA1/2; ATM; ATM- and Rad3-related protein kinase; ATR; Ataxia-telangiectasia; CaBP; Cerebellar organotypic cultures; Chromatin; DDR; DNA damage response; DNA dependent protein kinase, catalytic subunit; DNA-PKcs; DSB; GFAP; H2AX; H3K9Me3; HDR; HP1α; HR; MRN complex; Mre11; Mre11/Rad50/Nbs1 complex; NBS; NHEJ; NLC; NeuN; Nijmegen breakage syndrome; PI3K; PIK-related kinases; SCAN1; ataxia with oculomotor apraxia type 1; ataxia-telangiectasia; ataxia-telangiectasia, mutated; ataxia-telangiectasia-like disorder/disease; calbindin protein (calbindin-D28K); double strand break; glial fibrillary acidic protein; heterochromatin protein 1alpha; histone 2AX; homologues recombination; homology-directed repair; iPS cells; induced pluripotent stem cells; meiotic recombination 11; neuron-like cell; neuronal nucleus; nonhomologues end-joining; p53 binding protein 1; phosphatidyl inositol kinase-related protein kinases; phosphatidylinositol 3- kinase; phosphorylated histone 2AX; spinocerebellar ataxia with axonal neuropathy; trimethylated lysine 9 of histone 3; γH2AX.
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