The research appears as the "Paper of the Week" in the October 8 issue of the Journal of Biological Chemistry, an American Society for Biochemistry and Molecular Biology journal.
Bcl-2 is a gene that, when mutated or inappropriately expressed, can cause a cell to become cancerous. Normally, bcl-2 produces a protein that inhibits cell death or apoptosis. This protein keeps death-promoting factors from producing holes in the mitochondria which can result in calcium and destructive proteins leaking out into the cell. However, the overexpression of bcl-2 in damaged cells can lead to the continued division of the mutated cells and eventually cancer.
The expression of the bcl-2 gene is regulated both transcriptionally and posttranscriptionally. One way bcl-2 levels are controlled is through an adenine and uracil-rich sequence of nucleotides in the 3' untranslated region of the bcl-2 mRNA. This sequence, called the AU-rich element, or ARE, recruits a number of proteins that destabilize the bcl-2 mRNA, resulting in its degradation.
A report that a region of RNA upstream of the ARE also affects mRNA stability motivated Dr. Jeong-Hwa Lee and his colleagues at the Catholic University of Korea to make a series of bcl-2 mRNA constructs with deletions around the ARE.
From these constructs, the investigators identified a region of 30 nucleotides outside the ARE that destabilizes bcl-2 mRNA both in the absence and in the presence of the ARE. Because the region is composed mostly of cytosine and adenine repeats, they named it the CA-repeated Region (CAR).
The discovery of a new region on the bcl-2 gene that controls its ex
Contact: Nicole Kresge
American Society for Biochemistry and Molecular Biology