FIG. 8.

Meis2b protein binds the ephA8 regulatory sequence cooperatively as heterodimers with Pbx protein. (A) Nucleotide sequences of the ephA8 regulatory sites used in this study. Core recognition elements for Meis and Pbx are indicated by ^ and *, respectively, above their sequences. (B) Full-length Meis2b binds weakly to 30-bp and 44-bp probes (lanes 2 and 9 from left). Pbx2 protein does not bind the 30-bp probe (lane 4 from left) but does bind very weakly to the 44-bp probe (lane 11 from left). Meis2b and Pbx2 together form a strong cooperative complex with a 44-bp probe (lane 13 from left), but not the 30-bp probe (lane 6 from left). Mock lysate was used to normalize the levels of lysate in the reactions where one of the translated proteins was missing. (C) The binding specificities of proteins in the multimeric DNA complexes were tested using specific antibodies or Meis2e protein as indicated above each lane (+). SS, antibody-protein complexes resulting from supershift analyses.