Drad21, a Drosophila rad21 homologue expressed in S-phase cells

Cohesin is an evolutionarily conserved multiprotein complex required to est ablish and maintain sister chromatid cohesion. Here, we report the cloning and initial characterization of the Drosophila homologue of the fission yea st rad21 cohesin subunit, called Drad21. The Drad21 coding region was local ized to centromeric heterochromatin and encodes a 715 amino acid (aa) prote in with 42% aa identity to vertebrate Rad21p-homologues, 25% with Scc1p/Mcd 1p (S. cerevisiae) and 28% with Rad21p (S. pombe). Sequences with similarit y to the sites of proteolytic cleavage identified in Scc1p/Mcd1p are not ev ident in DRAD21. Northern blot and mRNA in-situ studies show that Drad21 is developmentally regulated, with high levels of expression in early embryog enesis, in S-phase cells of proliferating imaginal tissues, and in the earl y endocycling cells of the embryonic gut. (C) 2000 Elsevier Science B.V. Al l rights reserved.