Independent determination of symmetry and polarity in the Drosophila eye.

Abstract

In each facet ofthe Drosophila compound eye, a cluster of photoreceptor cells assumes an asymmetric trapezoidal pattern. These (11,12) as well as ectopic equators (5). These studies suggest that the direction of furrow progression plays an important role in controlling both ommatidial polarity and equator. However, it is unclear whether ommatidial polarity and more global determinants are determined by the same mechanisms.Morphogenetic processes involved in cuticular polarity formation have been studied using strains referred to as "polarity" mutants that have altered orientations of hairs and bristles (13). Interestingly, some polarity mutants, including spiny legs (sple) (14, 15), dishevelled (dsh) (16), and frizzled (fz) (17, 18), also show abnormal polarity of the photoreceptor clusters, providing some clues to study genetic mechanisms underlying the ommatidial polarity formation.Among several polarity mutants, sple shows remarkably specific pattern defects: the majority of abnormal ommatidia in the sple eye are only dorsoventrally reversed and show complete 90°r otations, whereas fz shows a mixture of eye phenotypes such as D/V and A/P reversals and incomplete rotation (19). We have isolated a P-lacW enhancer trap strain in which w+ gene expression is restricted to the dorsal domain providing a useful D/V marker. We here address the relationship between the global mirror symmetry and the local ommatidial polarity, using the mutant sple and the P-lacW enhancer trap marker. MATERIALS AND METHODSFly Stocks. Bl-12 was isolated from an enhancer trap screen (unpublished results) using the procedure described in Bier et al. (4). Bl-12 contains a single P-lacW insertion at the 69 D region of the third chromosome (data not shown). Homozygosity for Bl-12 causes lethality. Occasionally (less than 1%),

Polarity determination in the Drosophila eye: a novel role for Unpaired and JAK/STAT signaling

“…) Upd is also known as outstretched and sisterless-C. The mirr-lacZ reporters B1-12 (Choi et al 1996) and l(2)f7 (Brodsky and Steller 1996) were also used. The FRT18A and FRT82B lines (Xu and Rubin 1993) -GFP,w + ] in the presence of a FLP source; 24-48 hr larvae were heat shocked for 45 min at 37°C followed by incubation at 18°C (UAS-Wg) or 25°C (UAS-Upd) until mid-third instar.…”

Planar cell polarity and tissue design: Shaping the Drosophila wing membrane

“…In the Drosophila eye, loss of either Ds or Sple activity results in a specific phenotype in which ommatidial chirality and orientation is altered, but the degree of ommatidial rotation remains normal. 24,25 In contrast, loss of Pk activity alone does not affect eye development. 16 This suggests that Ds and Sple control the same aspects of eye development, which are independent of Pk activity.…”

Initial state of theDrosophilaeye before dorsoventral specification is equivalent to ventral

“…Stock used were y w; FRT82 pnr vx6 /TM6B, a null allele of pnr (Heitzler et al, 1996); y w hsFLP 122 ; iro DFM3 FRT80 /TM6B ; y w; mirr B1-12 /TM6B (Choi et al, 1996); y w eyFLP (Newsome et al, 2000); y w hsFLP 122 (Struhl and Basler, 1993); UAS-Ser DN (Hukriede et al, 1997);yw;, FRT42D, L rev6-3 /CyO and UAS-L (Chern and Choi, 2002); ey-GAL4 (Hazelett et al, 1998); pnr-GAL4 ; UAS-Ush (Fossett et al, 2001) and P{UAS-GFP.S65T/T10} (B. J. Dickson, unpublished). These stocks are described in FlyBase (http://flybase.bio.indiana.edu).…”