ISSN:
1365-2958
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
The β recombinase is unable to mediate in vitro DNA recombination between two directly oriented recombination sites unless a bacterial chromatin-associated protein (Bacillus subtilis Hbsu or Eschrichia coli HU) is provided. By electron microscopy, we show that the role of Hbsu is to help in joining the recombination sites to form a stable synaptic complex. Some evidence supports the fact that Hbsu works by recognizing and stabilizing a DNA structure at the recombination site, rather than by serving as a bridge between β recombinase dimers through a protein-protein interaction. We show that the mammalian HMG1 protein, which shares neither sequence nor structural homology with Hbsu, can also stimulate β-mediated recombination. These chromatin-associated proteins share the property of binding to DNA in a relatively non-specific fashion, bending it, and having a marked preference for altered DNA structures. Hbsu, HU or HMG1 proteins probably bind specifically at the crossing-over region, since at limiting protein-DNA molar ratios they could not be outcompeted by an excess of a DNA lacking the crossing over site. Distamycin, a minor groove binder that induces local distortions in DNA, did not affect the binding of β protein to DNA, but inhibited the formation of the synaptic complex.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2958.1995.mmi_18030471.x
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