MARS MISSION UPDATE

Genes are organized as chromatin domains and positioned in the nucleus through regions of nuclear matrix association, termed MARs. Although well studied, the mechanisms regulating expression of the beta-globin locus remain an enigma. Here, we show that certain MAR sequences of th e beta-globin locus are conserved and reiterated throughout the genome in association with other genes of the hematopoietic lineage. Further , the density of the MARs within the beta-globin locus and the sharing of these sequences by the various members of this gene cluster sugges t that they may provide critical gene regulatory components. (C) 1998 Academic Press.