PT  - JOURNAL ARTICLE
AU  - Blair, S.S.
TI  - Engrailed expression in the anterior lineage compartment of the developing wing blade of Drosophila
DP  - 1992 May 01
TA  - Development
PG  - 21--33
VI  - 115
IP  - 1
4099  - http://dev.biologists.org/content/115/1/21.short
4100  - http://dev.biologists.org/content/115/1/21.full
SO  - Development1992 May 01; 115
AB  - The developing wing of Drosophila melanogaster was examined at larval and pupal stages of development to determine whether the anterior-posterior lineage boundary, as identified by lineage restrictions, was congruent with the boundaries defined by the expression of posterior-specific (engrailed, invected), and anterior-specific (cubitus interruptus-D) genes. The lineage boundary was identified by marking mitotic recombinant clones, using an enhancer trap line with ubiquitous beta-gal expression in imaginal tissues; clones of +/+ cells were identified by their lack of beta-gal expression. Domains of gene expression were localized using antibodies and gene specific lacZ constructs. Surprisingly, it was found that engrailed expression extended a small distance into the anterior lineage compartment of the wing blade, as identified with anti-en/inv mAb, anti-en polyclonal antiserum, or an en-promoter-lacZ insert, ryxho25. This anterior expression was not present in early third instar discs, but appeared during subsequent larval and pupal development. In contrast, the expression of cubitus interruptus-D, as identified using the ci-Dplac insert, appeared to be limited to the anterior lineage compartment. Thus, en expression is not limited to cells from the posterior lineage compartment, and en and ci-D activities can overlap in a region just anterior to the lineage compartment boundary in the developing wing. The lineage boundary could also be identified by a line of aligned cells in the prospective wing blade region of wandering third instar discs. A decapentaplegic-lacZ construct was expressed in a stripe several cells anterior to the lineage boundary, and did not define or overlap into the posterior lineage compartment.