Table 3

Larval foraging trail lengths (in centimeters) indg2-cDNA transgenic flies and PKG enzyme activity assay levels (in pmol/min per milligram protein) in the larval CNS. Results are given as mean ± SE, with sample size in parentheses.

Strain Foraging behavior*PKG enzyme activity
forR (rover)9.2  ±  0.53 (44) 11.2  ±  0.64 (13)
dg2-cDNA (transgenic) 8.9  ±  0.63 (44) 12.3  ±  0.56 (13)
w1; fors(host for transformation) 4.6  ±  0.29 (47) 10.0  ±  0.65 (12)
  • * dg2-cDNA transgenic strain had significantly longer mean trail lengths [one-way ANOVA, F(1, 89) = 40.66,P < 0.0001] and significantly higher PKG enzyme activities [ANOVA, F(1, 23) = 7.15, P < 0.014] than did the w1; fors strain. TheforR rover control and thedg2-cDNA transgenic larvae did not significantly differ in their foraging behavior and PKG enzyme activities; this demonstrated full rescue of rover behavior in the dg2-cDNA transgenic larvae (11).

  • The CNS of 25 third-instar larvae from dg2-cDNA transgenic strain andw1; for swere dissected and placed on ice in the extraction buffer [25 mM tris (pH 7.4), 1 mM EDTA, 2 mM EGTA, 5 mM β-mercaptoethanol, PMSF (1 μg/ml), leupeptin (1 μg/ml), aprotinin (4 μg/ml), and 0.05% Triton X-100]. Tissue samples were homogenized in 100 μl of extraction buffer and frozen at –70°C, thawed on ice, quickly centrifuged, and supernatants were immediately used for the assay. Three determinations gave mean ± SD. cAMP kinase activity of 69 ± 7 pmol/min/mg protein for dg2-cDNA transgenic strain and 65 ± 7 pmol/min per milligram for w1; for s. Under heat-shock conditions [two cycles of 15 min at 37°C and 15 min rest at 25°C, and 2.25 hours rest at 25°C], the PKG enzyme activities (mean ± SE) of dissected CNS of the dg2-cDNA transgenic strain = 19.51 ± 0.77 (n = 10) andw1; for s = 12.62 ± 0.67 (n = 9) differed [one-way, ANOVA,F(1, 17) = 44.46, P < 0.0001]; thefor R rover control PKG activity under heat shock was 14.35 ± 0.43 (n = 3).