P-element mutagenesis using the SynP1+P2 strain containing the P{lacW}SynP1 and P{lacW}SynP2 insertions has resulted in the deletion of the entire genomic region between the two insertions, such that Timp exons 2-5 and Syn exons 1-8 are absent.
Timp28 mutants are homozygous subvital with temperature-sensitive penetrance. At a culture temperature of 18[o]C the number of adult flies developing from fertilized eggs is decreased by 38% in comparison to controls. 6% of Timp28 mutant flies die at the pupal stage or fail to fully eclose from the pupal case at 18[o]C, in comparison to about 1% in the control strains. At 25[o]C, the number of adult flies developing from fertilized eggs is decreased by 20% compared to wild-type. Vitality and fertility of Timp28 mutant adults are likewise drastically reduced. Half of the adult flies die within 8 days of eclosion. Compared to wild-type females, the number of eggs laid by Timp28 females is reduced about tenfold.
Timp28 adults show morphological defects in the wings and the abdomen with penetrance and expressivity being cold-sensitive. When raised at 18[o]C, the wings of 32% of 1-2 days-old Timp28 flies show patches of variable size that are permanently inflated with lymph, compared to only 17% at 25[o]C. The size of these patches enlarges with age. Occasionally, there are structural defects in the wing veins and serrated wings. When grown at 18[o]C, 19% of 1-2-days old Timp28 flies have oversized abdomens which are filled with liquid and in some cases with a small gas bubble. Sections through such abdomens show that the inner organs are missing or displaced by liquid, coming mainly from an overfilled gut. In some individuals this liquid disperses throughout the body cavity including the eyes and internal abdominal tissues are progressively lysed rendering the abdomen translucent. A few hours later the flies die.
Three-days old Timp28 flies are severely impaired in their fast phototactic responses. Qualitative tests show that, in contrast to wild-type, Timp28 flies exhibit negative phototaxis.
