Figure 2: Pol III co-occupies methylated SINEs with MBPs.
(a) Semiquantitative ChIP assay in A31 fibroblasts showing specific binding of TFIIIB, TFIIIC and pol III to B1 and B2 loci, as well as 7SL, but not the Apo-E gene. Histone H3 and TAFI48 provide positive and negative controls, respectively. (b) Semiquantitative ChIP assay in HeLa cells showing occupancy of pol III, TFIIIB and TFIIIC at Alu loci from chromosomes 6, 10, 19 and 22, as well as 7SL and Apo-E genes. ChIPs for histone H3 and TAFI48 provide positive and negative controls, respectively. No antibody was used for the mock sample. (c) Mean±s.e.m. of the percentage input bound in three independent ChIP–quantitative PCR (qPCR) assays in HeLa cells, of the indicated proteins at individual Alu loci from chromosomes 6, 10, 19 and 22, as well as 7SL and Apo-E loci and Alu PV subfamily consensus. ChIPs for histone H3 and TAFI48 provide positive and negative controls, respectively. No antibody was used for the mock samples. P values are calculated by t-test. (d) Mean±s.e.m. of four independent sequential ChIP–qPCR assays in which DNA immunoprecipitated from HeLa cells using pol III antibody was reprecipitated using antibodies against pol III, TFIIIB, TAFI48 (negative control), MBD1, MBD2 and MeCP2, as indicated. No TAFI48 signal was detected on Alu(c6).
