Grk overexpression still induces a gain-of-function phenotype in the absence of elongated GSLs
| Occurrence of the dorsalization phenotype (%) | |||||||
|---|---|---|---|---|---|---|---|
| Genotype | No phenotype  | Weak  | Medium  | Strong  | |||
| w;;nosGAL4/UASPmbgrkmyc (n=300) | 9.7±2 | 11.3±3.5 | 56±2 | 23±1 | |||
| brn;;nosGAL4/UASPmbgrkmyc (n=300) | 0±0 | 0±0 | 100±0 | 0±0 | |||
| Occurrence of the dorsalization phenotype (%) | |||||||
|---|---|---|---|---|---|---|---|
| Genotype | No phenotype | Weak | Medium | Strong | |||
| w;;nosGAL4/UASPmbgrkmyc (n=300) | 9.7±2 | 11.3±3.5 | 56±2 | 23±1 | |||
| brn;;nosGAL4/UASPmbgrkmyc (n=300) | 0±0 | 0±0 | 100±0 | 0±0 | |||
Germ line overexpression of grk in a wild-type background produces a range of dorsalization phenotypes that can be classified into four groups:`no phenotype' (i.e. eggs that resemble wild-type); `weak', which corresponds to eggs that have RAs set further apart; `medium', in which appendage material surrounds the entire anterior circumference of the egg; and `strong', in which operculum-like material (anterior dorsal midline fate) occupies the entire anterior circumference of the egg (Queenan et al., 1997). Upon germ line grk overexpression in the brn mutant background, eggs are dorsalized, indicating that Grk is secreted and active in the absence of GSLs.