Multiple weak determinants spread across the SR NTD sequence guide their binding specificity in mammalian genomes. (A) A NTD truncation series reveals that the binding profiles of AR and PR are gradually shifted with increasing length. The NTDs were gradually shortened by removing defined amino acid (AA) blocks, as shown in the schemes. Shown are the correlations in peak binding between the indicated truncation mutants (note that all repeats are included). (B–D) Truncations of the NTD of AR result in a gradual loss of binding peaks. (B) The gradual loss of LBD-deleted mutant-dominated peaks and gain of DBD mutant-dominated peaks upon NTD truncations (top; Methods), as well as the mean signal of the dominated peaks of the two mutants (bottom). (C,D) Log₂ fold-change of signal on the ΔLBD-dominated peaks versus DBD-dominated peaks, as defined above, is shown in C, and two genomic tracks are shown as a representative example of the loss of LBD-deleted (ΔLBD) mutant peaks and gain of DBD mutant peaks (D; Methods).