Reference Report

Reference
Citation	Senti, K., Keleman, K., Eisenhaber, F., Dickson, B.J. (2000). brakeless is required for lamina targeting of R1-R6 axons in the Drosophila visual system. Development 127(11): 2291--2301. (Export to RIS)
FlyBase ID	FBrf0127316
Publication Type	Research paper
PubMed ID	10804172
PubMed Abstract	Photoreceptors in the Drosophila eye project their axons retinotopically to targets in the optic lobe of the brain. The axons of photoreceptor cells R1-R6 terminate in the first optic ganglion, the lamina, while R7 and R8 axons project through the lamina to terminate in distinct layers of the second ganglion, the medulla. Here we report the identification of the gene brakeless (bks) and show that its function is required in the developing eye specifically for the lamina targeting of R1-R6 axons. In mosaic animals lacking bks function in the eye, R1-R6 axons project through the lamina to terminate in the medulla. Other aspects of visual system development appear completely normal: photoreceptor and lamina cell fates are correctly specified, R7 axons correctly target the medulla, and both correctly targeted R7 axons and mistargeted R1-R6 axons maintain their retinotopic order with respect to both anteroposterior and dorsoventral axes. bks encodes two unusually hydrophilic nuclear protein isoforms, one of which contains a putative C(2)H(2) zinc finger domain. Transgenic expression of either Bks isoform is sufficient to restore the lamina targeting of R1-R6 axons in bks mosaics, but not to retarget R7 or R8 axons to the lamina. These data demonstrate the existence of a lamina-specific targeting mechanism for R1-R6 axons in the Drosophila visual system, and provide the first entry point in the molecular characterization of this process.
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Language of Publication	English
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Publication Type	Journal
Abbreviation	Development
Title	Development
Publication Year	1987-
ISBN/ISSN	0950-1991
Data from Reference
Aberrations (4)
	Df(2R)PC4 Df(2R)PC29 Df(2R)Pcl11B Df(2R)PclW15
Alleles (14)
	Ecol\lacZ^{bi.T:Btau\MAPT} Ecol\lacZ^GMR.C.hs Ecol\lacZ^{ninaE.T:Btau\MAPT} Ecol\lacZ^{Rh4.T:Btau\MAPT} Ecol\lacZ^{ro.T:Btau\MAPT} sbb¹ sbb² sbb⁰⁴⁴⁴⁰ sbb⁰⁴⁵²⁵ sbb^{A.GMR.T:Hsap\MYC} sbb^A.GMR sbb^{B.GMR.T:Hsap\MYC} sbb^B.GMR sbb^k00702
Constructs (9)
	P{bi-taulacZ.N} P{GMR-lacZ.C(38.1)} P{GMR-sbb.A.myc} P{GMR-sbb.A} P{GMR-sbb.B.myc} P{GMR-sbb.B} P{ninaE-taulacZ.N} P{Rh4-taulacZ.N} P{ro.lacZ-tau.G}
Genes (9)
	Btau\MAPT chp Ecol\lacZ elav futsch repo sbb T:Btau\MAPT T:Hsap\MYC
Insertions (3)
	P{lacW}sbb^k00702 P{PZ}sbb⁰⁴⁴⁴⁰ P{PZ}sbb⁰⁴⁵²⁵