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Biophys J. 2017 Dec 19;113(12):2609-2620. doi: 10.1016/j.bpj.2017.10.026.

Nanoscale Assembly of High-Mobility Group AT-Hook 2 Protein with DNA Replication Fork.

Author information

1
Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada.
2
Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada; Manitoba Institute for Materials, University of Manitoba, Winnipeg, Manitoba, Canada.
3
Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada; Manitoba Institute for Materials, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada.
4
Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada; Discovery Lab, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. Electronic address: trushar.patel@uleth.ca.
5
Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada. Electronic address: joerg.stetefeld@umanitoba.ca.

Abstract

High mobility group AT-hook 2 (HMGA2) protein is composed of three AT-hook domains. HMGA2 expresses at high levels in both embryonic stem cells and cancer cells, where it interacts with and stabilizes replication forks (RFs), resulting in elevated cell proliferation rates. In this study, we demonstrated that HMGA2 knockdown reduces cell proliferation. To understand the features required for interaction between HMGA2 and RFs, we studied the solution structure of HMGA2, free and in complex with RFs, using an integrated host of biophysical techniques. Circular dichroism and NMR experiments confirmed the disordered state of unbound HMGA2. Dynamic light scattering and sedimentation velocity experiments demonstrated that HMGA2 and RF are monodisperse in solution, and form an equimolar complex. Small-angle x-ray scattering studies revealed that HMGA2 binds in a side-by-side orientation to RF where 3 AT-hooks act as a clamp to wrap around a distorted RF. Thus, our data provide insights into how HMGA2 interacts with stalled RFs and the function of the process.

PMID:
29262356
PMCID:
PMC5771026
DOI:
10.1016/j.bpj.2017.10.026
[Indexed for MEDLINE]
Free PMC Article

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