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A protein for two reasons –

The transcription factor Bur1-Bur2 participates in DNA repair

Munich, 11/24/2010

Cellular function is dependent on gene expression -- the conversion of genetic information encoded in DNA sequences into the amino acid sequences of proteins, which are the workhorses in all cells. The first step in this process is controlled by transcription factors. The protein complex Bur1-Bur2 is a transcription factor, but an international research team led by LMU biologist Dr. Katja Sträßer now shows that it is actually multitalented. It acts in the repair of damaged DNA too. DNA is subject to attack by physical and chemical agents, and cells have developed elaborate ways of repairing the resulting damage. “We now want to dissect the precise molecular function of Bur1-Bur2,” says Sträßer. “DNA damage can lead to cancer and other diseases, so it is important to understand the process of DNA repair. Detailed insights into the mechanisms of repair could provide opportunities for the development of novel treatments.” (Journal of Biological Chemistry online, November 2010)

The primary goal of Katja Sträßer’s research is to understand gene expression in molecular detail. Gene expression begins in the cell nucleus with the copying (transcription) of a defined DNA sequence into RNA. The RNA is then exported to the cytoplasm, where its sequence is decoded to direct the synthesis of a specific protein. Sträßer’s group is particularly interested in a protein complex in yeast called TREX, which links the transcription step to RNA export. In earlier work, the group found that Bur1-Bur2, which consists of two different subunits, interacts with TREX.

Sträßer’s team has now discovered that Bur1-Bur2 interacts with a second protein complex, RPA, which is required for homologous recombination. This process involves sequence exchange between DNA molecules, and is used in DNA repair to replace defective or deleted segments of DNA by copying the correct sequence from undamaged DNA. In addition, RPA plays a part in other functional pathways that maintain the integrity of the genome. "Cells in which Bur1-Bur2 is missing or defective become more sensitive to DNA-damaging agents,“ reports Sträßer. “The protein obviously plays an important role as an interaction partner. So our next goal is to clarify the molecular function of the Bur1-Bur2 complex, especially because a better understanding of DNA repair mechanisms might lead to new therapies for diseases like cancer.“

The project was carried out in collaboration with Professor Patrick Cramer (LMU Genzentrum) and Professor Michael Lisby (Copenhagen University) and financed by LMU’s Center for Integrated Protein Science (CIPSM) and SFB 646 (Networks in Gene Expression and Maintenance).


Dr. Katja Sträßer
Gene Center LMU Munich
Phone: +49 (0) 89 / 2180 – 76937

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