Transgenic construct used to study Polycomb Group response elements (PREs) from the Bithorax complex. Contains: a 3.7kb HindIII fragment carrying Fab-7 (from position +122 to +126 on the BXC map) - the Ecol\lacZUAS.l5 reporter - a 5.2kb EcoRI fragment carrying the MCP region (position +94 to +99 on the BXC map) - the w+mC marker. The Fab-7 PRE sequence is oriented such that the proximal end of the element is closest to the UAS sequences of the Ecol\lacZUAS.l5 reporter. The MCP sequence is oriented such that the proximal end of the element is closest to the 3' end of the Ecol\lacZUAS.l5 reporter.