Supplementary Figure 1: Optimization of the cross-linking time.
5 g freshly collected SDX were merged into Crosslinking Buffer, and crosslinking performed by vacuum (5 min)/release/mix at room temperature, three times (15 min), six times (30 min) or eight times (40 min). A positive direct target PtrMYB021 of PtrSND1-B16,7 was used. PtrACTIN was used as a negative control. The binding of PtrSND1-B1 to the promoter of PtrMYB021 or PtrACTIN was determined by ChIP using 5 μl of anti-PtrSND1-B1 antibodies followed by detection using ChIP-PCR. Vacuum (5 min)/release/mix at room temperature, six times (30 min) was determined to be optimal. Input, Mock and Anti-B1 are PCR reactions using the chromatin preparations before immunoprecipitation, immunoprecipitated with preimmune serum and immunoprecipitated with anti-PtrSND1-B1 antibody, respectively. Three independent biological replicates of ChIP assays were performed, and the results of one biological replicate are shown. The primers used are described in ref. 7.
