Information about FRT18A
Updated January 14, 2014
Stock Center logo
July 2002 - Dominic Ebacher of the Panganiban lab reports that they saw anomalous results with flies carrying P{neoFRT}18A and ey-FLP and have subsequently shown that in the presence of continuous FLPase, P{neoFRT}18A is 75% lethal and 100% of the escapers have severe eye and head defects. Test crosses with other P{neoFRT}18A chromosomes and other FLPase stocks (including ey-FLP on other chromosomes) indicate that these phenotypes are due to the P{neoFRT}18A chromosome.

They do not find this effect when using P{neoFRT}19A stocks. The lethality and developmental abnormalities are observed with both male and female flies carrying a P{neoFRT}18A chromosome, so the defects are not due to inter-chromosomal recombination.

They suspect that the original P{neoFRT}18A chromosome has an aberration (perhaps another FRT site near the one at 18A) and that this has been transmitted to recombinant chromosomes carrying P{neoFRT}18A. If another FRT is present, recombination between the two FRT sites could delete essential genes, leading to cell lethality and head defects.

They also report that, consistent with their results, Seth Blair observes wing disc defects using flies carrying P{neoFRT}18A and ap-GAL4, a wing driver. Thus P{neoFRT}18A is probably cell lethal in the presence of continuous FLPase. In light of this, they (and we) recommend that researchers use P{neoFRT}18A) only with transient (e.g. heat shock-inducible) FLPase, and that P{neoFRT}19A is used whenever feasible.