Abstract
The Plk1-interacting checkpoint helicase (PICH) protein localizes to ultrafine anaphase bridges (UFBs) in mitosis alongside a complex of DNA repair proteins, including the Bloom's syndrome protein (BLM). However, very little is known about the function of PICH or how it is recruited to UFBs. Using a combination of microfluidics, fluorescence microscopy, and optical tweezers, we have defined the properties of PICH in an in vitro model of an anaphase bridge. We show that PICH binds with a remarkably high affinity to duplex DNA, resulting in ATP-dependent protein translocation and extension of the DNA. Most strikingly, the affinity of PICH for binding DNA increases with tension-induced DNA stretching, which mimics the effect of the mitotic spindle on a UFB. PICH binding also appears to diminish force-induced DNA melting. We propose a model in which PICH recognizes and stabilizes DNA under tension during anaphase, thereby facilitating the resolution of entangled sister chromatids.
| Original language | English |
|---|---|
| Journal | Molecular Cell |
| Volume | 51 |
| Issue number | 5 |
| Pages (from-to) | 691-701 |
| Number of pages | 11 |
| ISSN | 1097-2765 |
| DOIs | |
| Publication status | Published - 12 Sept 2013 |
Keywords
- Adenosine Triphosphate
- Anaphase
- Animals
- Chromatids
- DNA Helicases
- Humans
- Microscopy, Fluorescence
- Nucleic Acid Heteroduplexes
- Nucleosomes
- Protein Transport
- Recombinant Proteins