Transgene that contains 1. a loxP cassette containing a 2.9kb Mcp element fragment, 2. an FRT cassette containing a 661bp bxd PRE fragment, 3. a w+* marker and 4. the intronless y+mDint reporter. The y reporter is in opposite orientation to the w+* marker (tail-to-tail orientation) and the Mcp fragment is oriented such that the end normally adjacent to iab-4 is closer to the FRT cassette.
The Flipper2 construct contains the 2.9kb EcoR1 MCP-PRE (polycomb response element) flanked by P1\loxP sites and the 661bp NdeI-PstI bxd PRE flanked by Scer\FRT sites. The markers w+* and y+mDint are present.