Figure 3.

tkv RNA expression is negatively regulated by D-mef2 in the egg chambers. Ovaries were dissected from Oregon-R (wt; A–D), D-mef2⁶⁵/D-mef2⁴²⁴ (mef2^−/−; E–G), w; P[w⁺, GAL4]^55B/P[w⁺, UAS-lacZ]^4–2-4B (UAS-lacZ; H), or w; P[w⁺, GAL4]^55B/P[w⁺, UAS-D-mef2] (UAS-mef2; I and J) and hybridized with digoxigenin-labeled tkv cDNA probes (A–G, and I and J) or stained for the β-galactosidase activity (H). Anterior is to the left. (A and E) Optical cross-sections of stage 9 and early eggs. (B and F) Optical cross-sections of stage 10A eggs. (C and D) Dorsal and ventral surface views of late-stage 10B eggs, respectively. Arrows point to the ventral population of CMFC that express tkv. (G) Optical cross-section of a stage 10B egg. In D-mef^−/−, tkv is overexpressed at stage 9 and later. Note that stage 10 eggs from D-mef2^−/− are smaller than the wild type. Other features are described in the text. (I and J) Dorsal and ventral surface views, respectively, of a stage 10B egg from a transgenic female w; P[w⁺, GAL4]^55B/P[w⁺, UAS-D-mef2]. This GAL4/UAS system directs ectopic overexpression in the anterior population of the O-FC as monitored in H by using the lacZ reporter gene (brackets). As a result of D-mef2 overexpression, the tkv expression is diminished in both the dorsal stripes and the ventral CMFC.