spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

Right arrow Help viewing high resolution images
Right arrow Return to article
(Downloading may take up to 30 seconds.
If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.


Figure 3


Fig. 3. Regulatory specificity determines cis-interactions at the BX-C. On the B-A-5 construct (top diagram), the IAB5 enhancer was placed 3' of the proximal abd-A-lacZ reporter gene. The distal CAT gene is under the control of the Abd-B promoter. In this configuration the IAB5 enhancer selects Abd-B over abd-A, so that the Abd-B-CAT reporter exhibits a three-stripe IAB5 expression pattern in parasegments 10, 12 and 14; this is readily detected in blastoderm-stage embryos (A) and germband-elongation-stage embryos (B), whereas abd-A-lacZ is silent (C). By contrast, the IAB2 enhancer on the 2-B-A-5 construct (lower diagram) does not interact with its normal endogenous target (abd-A), but directs expression from the Abd-B-CAT gene in parasegments 7 (black arrow), 9, 11 and 13. In blastoderm-stage (D) and germ band elongation-stage embryos (E), a composite IAB2-IAB5-driven expression pattern is detected. The inactivity of the lacZ reporter on this construct (F) suggests that IAB2 only interacts with the most proximal promoter.





Right arrow Return to article