Fig. 3. Electrophoretic mobility shift assays demonstrating binding of FoxA4a/Pintallavis and Xvent2 with 14 and 22 bp elements from the Xanf1 promoter. (A,B) The reaction mixtures are as follows: lane 1, extract from oocytes microinjected with EGFP mRNA (control); lane 2, extract from oocytes microinjected with mRNA of FoxA4a/Pintallavis (A) or Xvent2 (B) diluted ten times with extract from oocytes microinjected with EGFP mRNA; lane 3, undiluted extract from oocytes microinjected with FoxA4a/Pintallavis (A) or Xvent2 (B) mRNA. (C) Lane 1, extract from oocytes microinjected with EGFP mRNA (control); lanes 2-4, extracts from oocytes microinjected with FoxA4a/Pintallavis mixed with normal (b) or two mutant (a,c) variants of the 14 bp element. Sequences of these variants are shown at the bottom of C. Sites of point mutations are underlined. (D) Core binding sites are indicated by the black and red lines for FoxA4a/Pintallavis and Xvent2, respectively; positions of binding sites located on the opposite DNA strand are underlined; possible binding site for FoxA4a/Pintallavis, which has one mismatch with the canonical binding site, is indicated by a broken line.