Understanding at the molecular level the consequences of defective ATR signalling in humans

Alcantara, Diana (2013) Understanding at the molecular level the consequences of defective ATR signalling in humans. Doctoral thesis (PhD), University of Sussex.

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Abstract

Ataxia telangiectasia and Rad3-related (ATR) is a central regulator of the mammalian DNA damage response. ATR is essential for survival, but hypomorphic mutations in ATR are associated with a subset of Seckel syndrome (ATR-S), a human condition characterised by microcephaly and severe growth retardation. I used patient-derived cell lines, as well as siRNA ATR inhibition to evaluate the impact of ATR deficiency in skeletal development (osteogenesis and chondrogenesis). The expression of chondroinduction-specific markers was also assessed and found impaired in ATR-S and PCNT-S patient-derived primary fibroblasts. I also found signs of insulin/PI3K/mTOR signalling deregulation in both ATR as well as PCNT deficient cells. A checkpoint defect in a disorder with a primary defect in mTOR pathway function, Donohue Syndrome, was also uncovered, establishing a link between defects in insulin/mTOR signalling with deregulation of the DNA damage response/checkpoint machinery, possibly via the glycogen synthase kinase 3β, GSK3 β, in human patient cells. I characterized cellular functional aspects of a novel microcephalic disorder, Microcephaly-Capillary Malformation Syndrome (MIC-CAP), caused by mutations in the endosome-associated deubiquitinase enzyme STAMBP. MIC-CAP cells exhibit compromised RAS-MAPK and PI3K-AKT pathway signalling, and defective ATR-dependent DDR, a common feature of microcephalic disorders. I also characterized aspects of PI3K-AKT signalling in two megalencephaly disorders harbouring novel mutations in core components of this pathway. Finally, I evaluated aspects of mTOR pathway function in cells from a genomic disorder caused by copy-number variation of 1q21.1.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Life Sciences > Biochemistry
Subjects: Q Science > QH Natural history > QH0301 Biology > QH0426 Genetics
Depositing User: Library Cataloguing
Date Deposited: 28 Jun 2013 11:49
Last Modified: 10 Sep 2015 15:26
URI: http://sro.sussex.ac.uk/id/eprint/45246

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