Fig. 1.
Expression of SIN3 187 affects levels of SIN3 220. a Schematic representing the different cell lines used in this study as well as the SIN3 isoform expressed in that line. b Western blot analysis of whole cell extract prepared from S2 cells, SIN3 220HA (left) and SIN3 187HA (right) cell lines. The expression of SIN3 220 with a C-terminal HA tag was driven by an inducible metallothionein promoter. Due to leakiness of the metallothionein promoter, the maximum level of expression of SIN3 220HA was achieved without induction. The SIN3 187HA cell line was treated with 0.07 M of CuSO4 to induce the transgene. Blots were probed with antibodies listed at the right. SIN3 PAN antibody recognizes all SIN3 isoforms. * denotes degradation product of SIN3 220HA. β-Actin or α-Tubulin was used as a loading control. c, d ChIP was performed on chromatin prepared from S2 (control), SIN3 220HA (c) or SIN3 187HA (d) cells using antibody against the HA tag. Immunoprecipitated DNA was quantified by quantitative PCR (qPCR). PCR amplification of ChIP DNA was carried out using primers designed within 500 bp upstream or downstream of the transcription start site (TSS) of all genes. Enrichment of SIN3 isoforms at gene targets is represented as a mean value of the percent of input ± standard error of the mean from three independent biological replicates