Transcriptional augmentation: modulation of gene expression by scaffold/matrix-attached regions (S/MAR elements).

For a long time S/MARs could only be characterized by the assays in vitro that led to their detection. Only recently a number of biological activities emerged that are common to most or all S/MARs that are detected by the classic procedures. This review focuses on the phenomenon of transcriptional augmentation that is found for genomically anchored or episomal genes and on a group of partially overlapping activities that are suited to maintain an episomal status. Further, it is attempted to correlate properties of the S/MAR-scaffold interaction with prominent or prototype protein binding partners.