Figure 4. Cse4 association with CDEI/II and CDEIII.

A) Cse4 nucleosome straddles the boundary between CDEII and CDEIII. Left: Map of the minichromosome utilized in the experiment. The construct contains 850 bp of pericentromeric sequence of chromosome IV, TRP1 marker, ARS1 and pUC19 sequence and has a size of 4.5 kb. There are two BglII sites: between CDEII and CDEIII in the CEN and in the ARS1. Right: BglII-treated chromatin of a strain 1498 (Cse4-HA6) carrying the minichromosome was immunoprecipitated with anti-HA antibody. DNA was eluted off the beads and separated on a 1% agarose gel. Southern blot was analyzed with a ³²P labeled probe for the pericentric CEN4 sequence (to detect the CDEI/II containing fragment) and a ³²P labeled probe for the TRP1 gene (to detect the CDEIII containing fragment). B) Both Cse4 and H3 are associated with the CDEI/II fragment. Left: Scheme of CDEI/II fragment excised from the minichromosome. Double-DIG labeled LNA probe for CDEI/II is indicated. Right: BglII-treated chromatin of strain 1498 (Cse4-HA6) and 1407 (H3-HA3) carrying the minichromosome with BglII sites between CDEII and CDEIII and 50 bp upstream of CDEI was cross-linked with formaldehyde and immunoprecipitated with anti-HA antibody. DNA was eluted off the beads and resolved on a 6% denaturing TBE polyacrylamide gel. Southern blot was analyzed with a double-DIG labeled LNA probe for CDEI/II. C) Both the CDEI/II and the CDEIII fragments can be co-immunoprecipitated with Cse4 and H3. Strains 1021 (wt), 1407 (H3-HA3), and 1498 (Cse4-HA6) carried the minichromosome where either the CDEI/II (left) or the CDEIII fragment (right) was flanked with BglII sites. BglII-treated chromatin was either not cross-linked or cross-linked with formaldehyde and immunoprecipitated with anti-HA antibody. The immunoprecipitated DNA was purified, size fractionated, and subjected to qPCR analysis. Bar graphs represent the average values from several independent experiments with SDs.