The mdm-2 oncogene is translocated and overexpressed in a murine plasmacytoma cell line expressing wild-type p53.

Abstract

The cellular p53 protein has been demonstrated to possess growth-inhibitory activity. Recent work suggests that the murine double minute gene (mdm-2) encodes a protein that may function as a cellular regulator or mediator of p53 function. We were interested in determining if the mdm-2 gene was overexpressed in mouse tumor cells, in particular mouse plasmacytomas that harbor wild type-p53 protein. A novel chromosomal translocation of the mdm-2 gene was detected in the SP2 cell line, that is derived from plasmacytoma MOPC21. The translocation results in a head-to-head arrangement of the mdm-2 gene (chromosome 10) with the immunoglobulin C kappa gene (chromosome 6), analogous to the translocations that activate the c-myc gene in murine plasmacytomas. Based on Northern blot analysis, the translocation induces a 10-fold elevation of mdm-2 RNA. Primer extension assays demonstrate that the 5' end of the mdm-2 RNA from the translocated gene is colinear with the 5' mdm-2 mRNA from an unrearranged gene, suggesting that the mRNA and encoded protein are unaltered. This chromosomal translocation represents the first example in which mdm-2 overexpression is activated by a genetic alteration other than gene amplification.

• Authors: S Berberich, M Cole
• Journal: Oncogene (Oncogene) Vol. 9 Issue 5 Pg. 1469-72 (May 1994) ISSN: 0950-9232 [Print] England
• PMID: 8152809 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• RNA, Neoplasm
• Tumor Suppressor Protein p53

Topics

• Animals
• Gene Expression Regulation, Neoplastic (genetics)
• Gene Rearrangement (genetics)
• Mice
• Plasmacytoma (genetics, metabolism)
• RNA, Neoplasm (metabolism)
• Translocation, Genetic
• Tumor Cells, Cultured
• Tumor Suppressor Protein p53 (genetics, metabolism)