Co-immunoprecipitation experiments suggest that RNAP-II complexes interact with Orc1p.

<p>(<b>a</b>) Western-blot analysis using 4H8 antibody for immunoprecipitated Orc1p, Orc2p, Cdc6p and RNAPII (using the 4H8, 8GW16 or H5 antibody). Hypophosphorylated (8GW16) and Ser2P-CTD (H5) phosphorylated at Ser5 (4H8). The same number of cells was used for each immunoprecipitation experiments (see materials and methods). Western-blot analysis using Orc2p or Cdc6p antibody, showed the interaction between Orc2p and Cdc6p. NO (no antibody) (<b>b</b>) Western-blot using Orc1p antibody for immunoprecipitation revealed that Ser2P-RNAP-II (H5) interacts with Orc1p. No interaction of RNAP-II with Orc2p was detected when Orc2p antibody was used for the western-blot (<b>c</b>) Co-IP results show that hypophosphorylated RNAP-II complexes (8GW16) interact with Orc1p, 4H8 and H5. The results for whole cell extraction (WCE) and immunoprecipitation performed without antibody (NO) are shown.