Bcl-2 Gene Breaking Point Area Mbr In Gene Expression Regulation

The bcl-2 major breakpoint region (mbr), located within the 3'-UTR of the bcl-2 gene, is the site of the most common chromosomal translocation, t(14;18) (q32;q21), which occurs in follicular lymphoma. The mbr forms a triplex DNA structure under physiological conditions and the triplex DNA structure plays an important role in DNA duplication and gene regulation. The bcl-2 mbr is a matrix attachment region (MAR). The special Al-rich sequence-binding protein (SATB1) binds immediately downstream of the mbr. SATB1 is also an important transcription factor which was involved in multiple gene regulation. These observations raise the possibility that the mbr may be involved in regulation of bcl-2 gene expression.To prove this possibility, we investigated the role of the bcl-2 mbr on reporter gene activity and the relevance of SATB1 to this function in a variety of cell lines. We found that the mbr up-regulated reporter gene expression. Deletion of the 37-bp AT-rich SATB1 binding site abolished the bcl-2 mbr regulation of reporter gene expression. Over expression of SATB1 enhanced bcl-2 mbr up-regulation of the reporter gene activity.Our data strongly demonstrated that the bcl-2 mbr possessed...