Novel functions for the CENP-A N-terminus during male meiosis in Drosophila melanogaster
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2018-03-23Author
Collins, Caitriona Mary
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Abstract
Recent 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.