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dc.contributor.advisorDunleavy, Elaine M.
dc.contributor.authorCollins, Caitriona Mary
dc.description.abstractRecent studies in plants and Drosophila suggest that CENP-A, the centromeric histone H3 variant and epigenetic marker of centromere localisation may have additional roles during meiosis. By immunoprecipitation and mass spectrometry we have identified components of the mitochondrial ATP synthase F1 complex as potential meiotic CENP-A interactors. Previous studies have identified a role for ATPsyn-α and ATPsyn-β in Drosophila male fertility and in addition, male Drosophalids express a testes specific paralogue of ATPsyn-β: ATPsyn-β-like, which is essential for male fertility. We report that testes specific knockdown of ATPsyn-α, ATPsyn-γ and ATPsyn-β-like subunits results in a defect in sister chromatid centromeric cohesion throughout meiosis I. Determination of whole tissue ATP levels after knockdown shows that ATP levels are reduced. However loss of cohesion severity does not correlate with ATP reduction indicating that it is likely that observed defect is not due to ATP depletion. Knockdown of CENP-A also leads to a similar loss of sister centromere cohesion during meiosis suggesting that a functional link between CENP-A and the ATP synthase F1 subunits exists. Indeed, using an in vitro interaction assay we have identified that CENP-A directly interacts with ATPsyn-α and by immunofluorescence microscopy we have found that ATPsyn-α and GFP-ATPsyn-β-like colocalise with CENP-A at centromeres in the germ-line. In our model, we hypothesise that centromeric CENP-A recruits ATPsyn-α and ATPsyn-β-like via its direct interaction with the ATPsyn-α subunit, at the centromere these subunits promote sister centromere cohesion in a mechanism independent of ATP production.en_IE
dc.publisherNUI Galway
dc.subjectATP synthaseen_IE
dc.subjectNatural sciencesen_IE
dc.titleNovel functions for the CENP-A N-terminus during male meiosis in Drosophila melanogasteren_IE
dc.local.noteThe centromere is a chromosomal domain which is visible as a constricted region on dividing chromosomes; it is the site of attachment of cell division machinery (the spindle) and it is essential for correct chromosome segregation. The chromosomal location of the centromere is epigenetically regulated by the presence of the histone protein, CENP-A. Indeed CENP-A has been implicated in many diseases of the cell cycle including many cancers and in infertility. Using Drosophila melanogaster as a model system we carried out a ‘fishing experiment’ to search for unknown protein interactions. Unexpectedly we uncovered a possible interaction between our histone protein CENP-A and the mitochondrial ATP synthase complex. ATP synthase is a highly conserved enzymatic structure, which is essential for ATP generation. Subsequently, it was confirmed that in Drosophila spermatocytes ATP synthase subunits ATPsyn-α and ATPsynβlike are in fact localising within the nucleus, to the centromere where they interact directly with CENP-A and are required for correct chromosome segregation during meiotic division.en_IE

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