Skip to main content
. 2010 Jul 22;6(7):e1001032. doi: 10.1371/journal.pgen.1001032

Figure 3. The RTS1 fork barrier at the MT locus triggers γH2A formation.

Figure 3

(A) Detailed landscape of γH2A in the MT locus as determined by ChIP-on-chip analysis in Figure 2A. The top diagram compares the MT locus configuration of the Donorless ChIP strain to sequences present on the Affymetrix S. pombe Tiling 1.0 FR microarray. Locations of key features correspond to the ChIP-on-chip data coordinates shown below. Both strains contain the RTS1 barrier. The ChIP strain is mating-type h+ at mat1, and lacks the silent donor alleles, which were replaced with a Leu2 marker. The microarray strain is mating-type h- at mat1 and contains only the mat3-h- donor allele. Both strains contain inverted repeat (IR) elements flanking the Leu2 or mat3 cassettes (purple arrows). Black rectangles below plot represent genes. Black boxes correspond to magnified regions shown in (B) and (C). (B) An example of preferential enrichment of γH2A in gene coding regions. (C) Detailed examination of γH2A at the IR boundary elements shows that γH2A spreading is restricted by B-box sequences (black triangles). (D) The RTS1 fork barrier leads to γH2A in the absence of the DSB. γH2A ChIP was performed in wild type and smt0 strains synchronized by cdc25-22 block. Diagram shows qPCR primer locations (black rectangles) relative to the DSB at Mat1. (E) γH2A formation at the MT-locus depends on Swi1-Swi3. γH2A ChIP was performed in the indicated strains as in (D) The locations of qPCR primers are indicated in diagram in (D).