Reference Report

Reference
Citation	Zeidler, M.P., Perrimon, N., Strutt, D.I. (1999). The four-jointed gene is required in the Drosophila eye for ommatidial polarity specification. Curr. Biol. 9(23): 1363--1372. (Export to RIS)
FlyBase ID	FBrf0123257
Publication Type	Research paper
PubMed ID	10607560
PubMed Abstract	The Drosophila eye is composed of about 800 ommatidia, each of which becomes dorsoventrally polarised in a process requiring signalling through the Notch, JAK/STAT and Wingless pathways. These three pathways are thought to act by setting up a gradient of a signalling molecule (or molecules) often referred to as the 'second signal'. Thus far, no candidate for a second signal has been identified.The four-jointed locus encodes a type II transmembrane protein that is expressed in a dorsoventral gradient in the developing eye disc. We have analysed the function and regulation of four-jointed during eye patterning. Loss-of-function clones or ectopic expression of four-jointed resulted in strong non-autonomous defects in ommatidial polarity on the dorsoventral axis. Ectopic expression experiments indicated that localised four-jointed expression was required at the time during development when ommatidial polarity was being determined. In contrast, complete removal of four-jointed function resulted in only a mild ommatidial polarity defect. Finally, we found that four-jointed expression was regulated by the Notch, JAK/STAT and Wingless pathways, consistent with it mediating their effects on ommatidial polarity.The clonal phenotypes, time of requirement and regulation of four-jointed are consistent with it acting in ommatidial polarity determination as a second signal downstream of Notch, JAK/STAT and Wingless. Interestingly, it appears to act redundantly with unknown factors in this process, providing an explanation for the previous failure to identify a second signal.
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Language of Publication	English
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Publication Type	Journal
Abbreviation	Curr. Biol.
Title	Current Biology
Publication Year	1991-
ISBN/ISSN	0960-9822
Data from Reference
Aberrations (2)
	Df(2R)PC4 Df(2R)Pcl11B
Alleles (16)
	Avic\GFP^{S65T.Scer\UAS} fj¹ fj^d1 fj^p1 fj^Scer\UAS.cZa fz¹ hop² N^ECN.Scer\UAS N^{int.G.Scer\UAS} os^Scer\UAS.cZa Scer\GAL4^bi-omb-Gal4 Scer\GAL4^ey.PH Scer\GAL4^GMR.PF Scer\GAL4^hs.2sev Scer\GAL4^{Scer\FRT.Act5C} wg^Scer\UAS.cKa
Constructs (9)
	P{AyGAL4} P{GAL4-ey.H} P{GAL4-Hsp70.sev} P{GAL4-ninaE.GMR} P{UAS-fj} P{UAS-N.ECN} P{UAS-N.intra.G} P{UAS-os.Z} P{UAS-wg.K}
Genes (10)
	Avic\GFP elav fj fz hop N os pros Scer\GAL4 wg
Insertions (1)
	P{GAL4}bi^omb-Gal4