Reference Report

Reference
Citation	Lawrence, P.A., Casal, J., Struhl, G. (1999). hedgehog and engrailed: pattern formation and polarity in the Drosophila abdomen. Development 126(11): 2431--2439. (Export to RIS)
FlyBase ID	FBrf0108517
Publication Type	Research paper
PubMed ID	10226002
PubMed Abstract	Like the Drosophila embryo, the abdomen of the adult consists of alternating anterior (A) and posterior (P) compartments. However the wing is made by only part of one A and part of one P compartment. The abdomen therefore offers an opportunity to compare two compartment borders (A/P is within the segment and P/A intervenes between two segments), and ask if they act differently in pattern formation. In the embryo, abdomen and wing P compartment cells express the selector gene engrailed and secrete Hedgehog protein whilst A compartment cells need the patched and smoothened genes in order to respond to Hedgehog. We made clones of cells with altered activities of the engrailed, patched and smoothened genes. Our results confirm (1) that the state of engrailed, whether 'off' or 'on', determines whether a cell is of A or P type and (2) that Hedgehog signalling, coming from the adjacent P compartments across both A/P and P/A boundaries, organises the pattern of all the A cells. We have uncovered four new aspects of compartments and engrailed in the abdomen. First, we show that engrailed acts in the A compartment: Hedgehog leaves the P cells and crosses the A/P boundary where it induces engrailed in a narrow band of A cells. engrailed causes these cells to form a special type of cuticle. No similar effect occurs when Hedgehog crosses the P/A border. Second, we look at the polarity changes induced by the clones, and build a working hypothesis that polarity is organised, in both compartments, by molecule(s) emanating from the A/P but not the P/A boundaries. Third, we show that both the A and P compartments are each divided into anterior and posterior subdomains. This additional stratification makes the A/P and the P/A boundaries fundamentally distinct from each other. Finally, we find that when engrailed is removed from P cells (of, say, segment A5) they transform not into A cells of the same segment, but into A cells of the same parasegment (segment A6).
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Secondary IDs
Language of Publication	English
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Parent Publication
Publication Type	Journal
Abbreviation	Development
Title	Development
Publication Year	1987-
ISBN/ISSN	0950-1991
Data from Reference
Aberrations (1)
	Df(2R)en^E
Alleles (17)
	Ecol\lacZ^en-Xho25 Ecol\lacZ^hh-P30 Ecol\lacZ^ptc.10.8L Ecol\lacZ^ptc-AT96 en^Es en^{Scer\FRT.Rnor\CD2.αTub84B} en^{Scer\FRT.Scer\UAS.T:Ivir\HA1} en^Scer\UAS.cGa en^{Scer\UAS.T:Ivir\HA1} ptc¹⁶ Rnor\CD2^hs.PJ Scer\FLP1^hs.PS Scer\GAL4^69B Scer\GAL4^{Scer\FRT.Rnor\CD2.Act5C} Scer\GAL4^Scer\FRT.Ubx Scer\GAL4^Ubx.PdC smo³
Constructs (10)
	P{GAL4-Act5C(FRT.CD2).P} P{GAL4-lacZ-Ubx(FRT.f⁺).dC} P{GAL4-lacZ-Ubx(-FRT).dC} P{hsp70-CD2.J} P{hsp70-flp} P{ptc-lacZ.10.8L} P{UAS(FRT.y⁺CD2)flu-en} P{UAS(-FRT)flu-en} P{UAS-en.G} P{αTub84B(FRT.y⁺CD2)en.Z2}
Genes (10)
	Ecol\lacZ en hh inv ptc Rnor\CD2 Scer\FLP1 Scer\GAL4 smo T:Ivir\HA1
Insertions (3)
	P{en-lacZ(Xho)}en^Xho25 P{lacZ}AT96 P{PZ}hh^P30