The Transcription Factor, Nm23H2, Binds to and Activates the Translocated c-myc Allele in Burkitt's Lymphoma

Lin Ji,Magdalena Arcinas,Linda M Boxer

doi:10.1074/jbc.270.22.13392

Abstract

We have identified an in vivo footprint over the PuF site on the translocated c-myc allele in Burkitt's lymphoma cells. The PuF site on the silent normal c-myc allele was unoccupied. We demonstrated by electrophoretic mobility shift assay, electrophoretic mobility shift assay with antibody, UV cross-linking followed by SDS-gel electrophoresis, and Western analysis that Nm23H2 in B cell nuclear extracts bound to the c-myc PuF site. Transfection experiments with c-myc promoter constructs in both DHL-9 and Raji cells revealed that the PuF site functioned as a positive regulatory element in B cells with a drop in activity with mutation of this site. Access to this site is blocked in the normal silent c-myc allele; these data suggest that the Nm23H2 protein is involved in deregulation of the translocated c-myc allele in Burkitt's lymphoma cells.

Highlights

From the Center for Molecular Biology in Medicine, VAMC, Palo Alto, California 94304 and the Department of Medicine, Stanford University School of Medicine, Stanford, California 94305
We have identified an in vivo footprint over the PuF site on the translocated c-myc allele in Burkitt's lymphoma cells
We demonstrated by electrophoretic mobility shift assay, electrophoretic mobility shift assay with antibody, UV cross-linking followed by SDS-gel electrophoresis, and Western analysis that Nm23H2 in B cell nuclear extracts bound to the e-myc PuF site

Summary

Introduction

We have identified an in vivo footprint over the PuF site on the translocated c-myc allele in Burkitt's lymphoma cells. We demonstrated by electrophoretic mobility shift assay, electrophoretic mobility shift assay with antibody, UV cross-linking followed by SDS-gel electrophoresis, and Western analysis that Nm23H2 in B cell nuclear extracts bound to the e-myc PuF site.

Results

Conclusion