The term
´S/MAR´ (scaffold/matrix attachment region), otherwise called
´SAR´ (scaffold-attachment region), or
´MAR´ (matrix-associated region), are sequences in the DNA of
eukaryotic chromosomes where the
nuclear matrix attaches. As architectural DNA components that organize the
genome of eukaryotes into functional units within the
cell nucleus, S/MARs mediate structural organization of the
chromatin within the nucleus. These elements constitute anchor points of the
DNA for the chromatin scaffold and serve to organize the chromatin into
structural domains. Studies on individual genes led to the conclusion that the dynamic and complex organization of the chromatin mediated by S/MAR elements plays an important role in the regulation of
gene expression.