Determinants of cohesin distribution among convergent sites. (a) Cohesin translocation and accumulation in response to rad21 upregulation. The Rad21-Pk9 pattern along a 40 kb region of chromosome 2 is compared in cells arrested in G2 (cdc25-22) or G1 (cdc10-129) when rad21 expression is low or high, respectively. Blue bars above and below the midline represent ORFs transcribed from left to right and opposite, respectively. (b) Sites where more than one ORF converge from both sides are more likely bound by cohesin. A schematic of class 1 and 2 convergent sites, and the percentage of these that are bound by cohesin along chromosome 2, are depicted. (c) Swi6 contributes to cohesin enrichment at centromeres, but not at convergent sites. The Rad21-Pk9 pattern at the centromere (outer, dg2 and dh2, and inner, imr2, centromeric repeat sequences are indicated), and along a 60 kb region on the right arm of chromosome 2, is shown in G2-arrested wild-type or swi6Δ cells. Cells were grown in medium lacking thiamine (-thi) to induce nmt2 (compare ). (d) More frequent cohesin occupation of convergent sites in meiosis. The cohesin pattern in G2-arrested cells (Rad21-Pk9) is compared to that in cells progressing through meiosis (Rec8-HA) along a 100 kb region on chromosome 2 (Rec8-HA profile from ).
Schmidt et al. Genome Biology 2009 10:R52 doi:10.1186/gb-2009-10-5-r52