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Fig. 3. Autonomous development of anterior and posterior compartments.
(A) Evolution of the P/A ratio during the second half of the larval
period in control M(3)67C/+, en-M+ and ci-M+
wing discs. In the control, the ratio increases during 3rd instar, whereas in
en-M+ discs the P/A ratio is approximately uniform. In
ci-M+, the ratio also increases, but it is significantly smaller
than control until day 6. At the end of the larval period the P/A ratio of
three classes of disc becomes the same. (B,C) A 2nd instar
wild-type disc shows wg expression (red) in the presumptive wing
pouch (B), and a similar aged en-M+ disc has virtually all
posterior cells transformed to M+, as indicated by the loss of the
GFP marker (C,C'). (D-E') expression of wg
and vg in en-M+ early third instar discs. The expression
of both genes is uncoupled in the anterior and posterior compartments, being
more advanced in the posterior one. (D,D') wg expression in the
posterior compartment is restricted to a proximal ring and the DV region,
whereas in the anterior compartment is more diffused in the wing pouch.
(E,E') vg expression is already expanding to the wing pouch in
the posterior compartment, whereas it is still restricted to the DV region in
the anterior compartment. (F-G') Similar results observed in
ci-M+ discs: there is a slight but detectable difference in
wg expression (F,F'), and more clear difference for vg
(G,G').
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