Figure 4. Nucleotide sequence of DNA fragments selected by the CASTing method.

dsDNA (CASTrandom oligonucleotide, Table S3, after synthesis of the complementary strand using PCR-specific primers CAST-F and CAST-R) was incubated with Zbed4 to form protein-DNA complexes that were immunoprecipitated using Zbed4 antibody and protein A-Sepharose beads. Bound DNA was extracted, PCR-amplified and used for the next round of CASTing. Three rounds of CASTing were performed. The amplified DNA fragments that interacted with Zbed4 were cloned and sequenced. A. Clones carrying poly-G tracts (bolded) and GC-box core sequences (underlined). B. Clones only carrying GC-box core sequences.