Figure 2. Structure of FoxP3 multimers in complex with T2G repeat DNA.

A. Cryo-EM structure of FoxP3^ΔN multimer in complex with four DNA molecules harboring (T₂G)₂₄. Within each dsDNA molecule, the T4G repeat strand is in black, whereas the complementary strand is in grey. FoxP3 subunits bound to different dsDNA are colored differently. Schematic (left), side view (middle) and top view (right) are shown. DNA^A and DNA^D are bridged by FoxP3 subunits labeled in dark blue and sky blue. The three dashed-line ovals at the top of the schematic represent the three subunits at the bottom, forming a closed loop.

B. Superposition of FoxP3^ΔN subunits bound to T2G repeat DNA^A (navy blue), DNA^B (blue), DNA^C (purple) and DNA^D (sky blue). Guanosine bases are indicated with spheres. Individual FoxP3 subunits interact with DNA in the identical manner, recognizing TGTTGTT sequence every 6 bp. This leads to FoxP3 molecules on each DNA forming two linear arrays on opposite sides of the DNA. No clear density for intra-DNA interaction was identified.

C. Inter-subunit interactions in the FoxP3-T2G repeat complex. Three distinct inter-DNA interactions (type IX-XI) were observed in two modes of DNA bridging: type IX and X interactions in mode 1 bridging, and type XI in mode 2 bridging. Both modes of DNA bridging occur in the antiparallel orientation.

See also Figure S3.