FIG. 8.
Pax6 binding contributes to area II activation. (A) The sequences of the mouse and human B8 and the B8 point mutant (T mt) are compared to a derived Pax6 binding oligonucleotide (P6Con [12]). The nucleotide similarity of the mouse and human sequences to the consensus Pax6 element is indicated with nonmatching nucleotides in lowercase. W is A or T; R is A or G; K is G or T; S is C or G; M is A or C. (B) Binding reactions were conducted with the B8-probeby using βTC-3 nuclear extracts (βTC-3 NE) or IVT Pax6. A 50-fold molar excess of unlabeled B8, B8 Tmt, and P6Con competitor was used. (C) Wild-type and mutant human area II:pTK constructs were transfected into βTC-3 and INS-1 cells. The ratio of mutant to wild-type area II:pTK activity is presented ± the standard error. Note that the B8 block mutant (B8mt) and point mutant activities (B8 Tmt) are reduced to a similar level relative to the wild type.