NHK-1 phosphorylates BAF to allow karyosome formation in the Drosophila oocyte nucleus
| Autor: | Oscar M. Lancaster, C. Fiona Cullen, Hiroyuki Ohkura |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Nuclear Envelope
Molecular Sequence Data Barrier-to-autointegration factor Protamine Kinase Models Biological Chromosomes Substrate Specificity Chromosome segregation 03 medical and health sciences Karyosome formation Report Catalytic Domain medicine Animals Drosophila Proteins Amino Acid Sequence Phosphorylation Kinase activity Research Articles 030304 developmental biology 0303 health sciences biology 030302 biochemistry & molecular biology Nuclear Proteins Cell Biology Molecular biology Chromatin Cell biology DNA-Binding Proteins Meiosis Cell nucleus Drosophila melanogaster Histone medicine.anatomical_structure Mutation Oocytes biology.protein Karyosome |
| Zdroj: | The Journal of Cell Biology |
| ISSN: | 1540-8140 0021-9525 |
| DOI: | 10.1083/jcb.200706067 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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