Dicentric Chromosome Stretching during Anaphase Reveals Roles of Sir2/Ku in Chromatin Compaction in Budding YeastV⃞
AUTOR(ES)
Thrower, Douglas A.
FONTE
The American Society for Cell Biology
RESUMO
We have used mitotic spindle forces to examine the role of Sir2 and Ku in chromatin compaction. Escherichia coli lac operator DNA was placed between two centromeres on a conditional dicentric chromosome in budding yeast cells and made visible by expression of a lac repressor–green fluorescent fusion protein. Centromeres on the same chromatid of a dicentric chromosome attach to opposite poles ∼50% of the time, resulting in chromosome bridges during anaphase. In cells deleted for yKU70, yKU80, or SIR2, a 10-kb region of the dicentric chromosome stretched along the spindle axis to a length of 6 μm during anaphase. On spindle disassembly, stretched chromatin recoiled to the bud neck and was partitioned to mother and daughter cells after cytokinesis and cell separation. Chromatin immunoprecipitation revealed that Sir2 localizes to the lacO region in response to activation of the dicentric chromosome. These findings indicate that Ku and Sir proteins are required for proper chromatin compaction within regions of a chromosome experiencing tension or DNA damage. The association of Sir2 with the affected region suggests a direct role in this process, which may include the formation of heterochromatic DNA.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=59714Documentos Relacionados
- Nuclear and Spindle Dynamics in Budding YeastV⃞
- The Septation Apparatus, an Autonomous System in Budding YeastV⃞
- Endoplasmic Reticulum Dynamics, Inheritance, and Cytoskeletal Interactions in Budding YeastV⃞
- Bud8p and Bud9p, Proteins That May Mark the Sites for Bipolar Budding in YeastV⃞
- Dominant-Lethal α-Tubulin Mutants Defective in Microtubule Depolymerization in YeastV⃞