The RB7 gene matrix attachments region (MAR) is a 1.2 kb
fragment isolated from the 3' ﬂanking region of the RB7
root-speciﬁc gene of tobacco.
When positioned on the flanking ends of gene cassettes, some the
RB7 MAR has been shown to increase expression of transgenes and to
reduce the incidence of gene silencing. It is hypothesized that
MARs may act to buffer effects from neighbouring chromosomal
sequences that could destabilize the expression of genes.