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DNA damage response in mammalian oocytes
Vachová, Veronika ; Šolc, Petr (advisor) ; Nevoral, Jan (referee)
During early embryonic development oocytes are arrested in prophase I of the first meiotic division, in which they can persist for years. After reaching sexual maturity and the luteinizing hormon surge resumption of meiosis and meiotic maturation occur. Oocytes are arrested again at metaphase of the second meiotic division. At this stage they are ovulated and waiting for a fertilisation. Oocytes are during their development exposed to factors that cause DNA damage, of which DNA double-strand breaks (DSBs) are the most serious threat. The maintaining of genome integrity is crucial for quality of oocytes, fertility and proper embryonic development. The mechanism of the oocyte response to DSBs presence is not fully understood and it seems to differ from somatic cells. We assume that DSBs are repaired during meiotic maturation probably by a mechanism of homologous recombination (HR). In this thesis we focuse on essencial recombinase RAD51, which participates in the repair by HR. We found that RAD51 inhibition leads to an increase of segregation errors in anaphase I. Using high resolution live cell imaging we observed chromosomal fragments and anaphase bridges. Immunofluorescence detection of DSBs-marker γH2AX showed increased amount of DSBs in prophase I and MII stage after RAD51 inhibition. Our data...
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Structure, function and importace of BRCA 1protein
Hojný, Jan ; Kleibl, Zdeněk (advisor) ; Falk, Martin (referee)
Studies of factors contributed to the development of hereditary breast and ovary cancers lead to the discovery of Breast Cancer 1 gene (BRCA1). The protein product of this tumor suppressor gene is nuclear phosphoprotein that plays a critical role in DNA repair and it is required for genome integrity control. The BRCA1 protein is the key component for correct assembly of reparation complexes formed in sites of DNA double strand breaks. Furthermore, BRCA1 protein is implicated in regulation of cell cycle checkpoints and it is also involved in regulation of gene expression in response to DNA damage. These activities suggest that BRCA1 protein plays a crucial role in orchestration of intracellular response to genotoxic DNA damage. Loss of BRCA1 functions leads to the DNA-damage repair mechanisms failure resulting in genomic instability and a tolerance of genomic alterations in affected cells. The genomic instability is the initial step toward early malignant transformation of cells lacking BRCA1 proteins. The aim of this work is to summarize the information about structure, functions known and the importance of BRCA1 protein with respect to the current discoveries enabling elucidation of versatile BRCA1-containing multiprotein complexes in which BRCA1 protein acts as the multiplatform interacting...
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DNA damage response in mammalian oocytes
Vachová, Veronika ; Šolc, Petr (advisor) ; Nevoral, Jan (referee)
During early embryonic development oocytes are arrested in prophase I of the first meiotic division, in which they can persist for years. After reaching sexual maturity and the luteinizing hormon surge resumption of meiosis and meiotic maturation occur. Oocytes are arrested again at metaphase of the second meiotic division. At this stage they are ovulated and waiting for a fertilisation. Oocytes are during their development exposed to factors that cause DNA damage, of which DNA double-strand breaks (DSBs) are the most serious threat. The maintaining of genome integrity is crucial for quality of oocytes, fertility and proper embryonic development. The mechanism of the oocyte response to DSBs presence is not fully understood and it seems to differ from somatic cells. We assume that DSBs are repaired during meiotic maturation probably by a mechanism of homologous recombination (HR). In this thesis we focuse on essencial recombinase RAD51, which participates in the repair by HR. We found that RAD51 inhibition leads to an increase of segregation errors in anaphase I. Using high resolution live cell imaging we observed chromosomal fragments and anaphase bridges. Immunofluorescence detection of DSBs-marker γH2AX showed increased amount of DSBs in prophase I and MII stage after RAD51 inhibition. Our data...
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Structure, function and importace of BRCA 1protein
Hojný, Jan ; Falk, Martin (referee) ; Kleibl, Zdeněk (advisor)
Studies of factors contributed to the development of hereditary breast and ovary cancers lead to the discovery of Breast Cancer 1 gene (BRCA1). The protein product of this tumor suppressor gene is nuclear phosphoprotein that plays a critical role in DNA repair and it is required for genome integrity control. The BRCA1 protein is the key component for correct assembly of reparation complexes formed in sites of DNA double strand breaks. Furthermore, BRCA1 protein is implicated in regulation of cell cycle checkpoints and it is also involved in regulation of gene expression in response to DNA damage. These activities suggest that BRCA1 protein plays a crucial role in orchestration of intracellular response to genotoxic DNA damage. Loss of BRCA1 functions leads to the DNA-damage repair mechanisms failure resulting in genomic instability and a tolerance of genomic alterations in affected cells. The genomic instability is the initial step toward early malignant transformation of cells lacking BRCA1 proteins. The aim of this work is to summarize the information about structure, functions known and the importance of BRCA1 protein with respect to the current discoveries enabling elucidation of versatile BRCA1-containing multiprotein complexes in which BRCA1 protein acts as the multiplatform interacting...
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