Fig. 6. GAGA binding sites are required for the maintenance of silencing. (A) Pattern of lacZ expression in the wing and haltere imaginal discs from larvae containing the MCP7 construct (138 bp MCP minimal sequence that includes the GAGA binding sites, Fig. 3). lacZ is silenced in the wing disc (ps4 and ps5) and in the anterior compartment of the haltere disc (ps5), but it is expressed in the posterior compartment of the haltere disc (ps6). (B) MCP7* construct (138 bp MCP minimal sequence with GAGA binding sites mutated as shown). Both the wing and haltere discs show strong derepression of lacZ.