The following information accompanied stocks donated to the Bloomington Stock Center by Peter Gallant, University of Würzburg.
P{alphaTub84B(FRT.Myc)GAL4.Bb}1 is a homozygous viable and fertile, X chromosome insertion located proximal to Myc (the rate of meiotic recombination between Myc and the insertion is rather high).
The level of Myc expression does not cause any dramatic effects. It is sufficient to rescue the lethality of the null mutation Myc4 in hemizygous males, but it only partially rescues the sterility of homozygous females. The difference in Myc levels between cells expressing ectopic Myc (from P{alphaTub84B(FRT.Myc)GAL4.Bb}) plus endogenous Myc and clones expressing only endogenous Myc is sufficient to trigger cell competition (see Moreno & Basler (2004; FBrf0174445)).