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Citation
Lancaster, O.M., Cullen, C.F., Ohkura, H. (2007). NHK-1 phosphorylates BAF to allow karyosome formation in the Drosophila oocyte nucleus.  J. Cell Biol. 179(5): 817--824.
FlyBase ID
FBrf0201757
Publication Type
Research paper
Abstract

Accurate chromosome segregation in meiosis requires dynamic changes in chromatin organization. In Drosophila melanogaster, upon completion of recombination, meiotic chromosomes form a single, compact cluster called the karyosome in an enlarged oocyte nucleus. This clustering is also found in humans; however, the mechanisms underlying karyosome formation are not understood. In this study, we report that phosphorylation of barrier to autointegration factor (BAF) by the conserved kinase nucleosomal histone kinase-1 (NHK-1; Drosophila Vrk1) has a critical function in karyosome formation. We find that the noncatalytic domain of NHK-1 is crucial for its kinase activity toward BAF, a protein that acts as a linker between chromatin and the nuclear envelope. A reduction of NHK-1 or expression of nonphosphorylatable BAF results in ectopic association of chromosomes with the nuclear envelope in oocytes. We propose that BAF phosphorylation by NHK-1 disrupts anchorage of chromosomes to the nuclear envelope, allowing karyosome formation in oocytes. These data provide the first mechanistic insight into how the karyosome forms.

PubMed ID
PubMed Central ID
PMC2099182 (PMC) (EuropePMC)
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    Language of Publication
    English
    Additional Languages of Abstract
    Parent Publication
    Publication Type
    Journal
    Abbreviation
    J. Cell Biol.
    Title
    Journal of Cell Biology
    Publication Year
    1966-
    ISBN/ISSN
    0021-9525
    Data From Reference
    Aberrations (1)
    Alleles (4)
    Genes (5)
    Physical Interactions (2)
    Natural transposons (1)
    Experimental Tools (1)
    Transgenic Constructs (3)