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Fig. 6. The TrkA minimal enhancer containing both Brn3a-binding-site
mutations has reduced activity in trigeminal ganglia. Representative
trigeminal ganglia ß-galactosidase activity driven by the wild-type
TrkA minimal enhancer (A,E), by a TrkA minimal enhancer
bearing a 5' Brn3a-binding-site mutation (B,F), by a TrkA
minimal enhancer bearing a 3' Brn3a-binding-site mutation (C,G), and by
a TrkA minimal enhancer bearing both Brn3a-site mutations (D,H,I) at
E13.5 and E17.5. Only the TrkA minimal enhancer with both mutations
caused severe reduction in enhancer activity at E13.5 and E17.5.