UASt regulatory sequences drive expression of robo1 cDNA sequences in which the 5' and 3' untranslated regions have been removed and the 5' sequences encoding the signal sequence have been replaced with sequences encoding the wg signal sequence (Tag:SS(wg)) followed by three copies of the Tag:HA tag.
Expression of roboScer\UAS.T:Ivir\HA1,T:wg under the control of Scer\GAL4109(2)80 results in significantly fewer dendritic branches in class IV neurons compared to controls, and an increase of the average branch length is observed. ddaC dendrites display many more filopodia-like processes at their tips at 21 and 22 hours after egg laying compared to sli2 and robo1 mutants. The average number of high order branches is reduced, but is double that of sli2 and robo1 mutants. Over expression does not lead to a significant dorsal overextension at 22 hours after egg laying.
In second instar larvae over-expression of roboScer\UAS.T:Ivir\HA1,T:wg under the control of Scer\GAL4109(2)80 results in a significant reduction in the number of branches in the dendritic trees of class IV neurons, and a decrease in total branch length is observed. Neurons fail to fully cover the appropriate target area and dendrite-free zones are observed. Dendrite branches often terminate with bulbous structures. No difference in the frequency of branch retraction or branch elongation is observed in real-time. The number of new branches formed is reduced, and a significant increase in the fraction of branches that do not modify their length over time is observed.
Expression of roboScer\UAS.T:Ivir\HA1,T:wg, driven by both Scer\GAL4how-24B and Scer\GAL4twi.PG, results in frequent myocardial cell alignment defects in embryos.
When roboScer\UAS.cKa is driven by Scer\GAL4ap-md544 Tv axons from the ventral nerve cord, avoid the midline and fail to innervate the dorsal neurohemal organs.
55% of ganglionic branches expressing roboScer\UAS.T:Ivir\HA1,T:wg under the control of Scer\GAL4bs.Term turn prematurely to migrate posteriorly before coming close to the midline and 16% stall at the level of the longitudinal tracts.
Expression of one copy of roboScer\UAS.T:Ivir\HA1,T:wg under the control of Scer\GAL4ap-md544 does not shift the position of the ap-expressing neurons which normally project along the medial edge of the longitudinal tract.
robo1UAS.Tag:HA,Tag:SS(wg)/Scer\GAL4bs.Term is a suppressor | partially of ganglionic tracheal branch primordium phenotype of robo24/robo28
Expression of roboScer\UAS.T:Ivir\HA1,T:wg under the control of Scer\GAL4bs.Term partially rescues the failure of ganglionic branches to enter the central nervous system that is seen in learobo2-4/learobo2-8 embryos and the weak midline crossing phenotype of the ganglionic branches seen in these embryos is also rescued.
robo1UAS.Tag:HA,Tag:SS(wg)/Scer\GAL4109(2)80 partially rescues robo11
Expression of roboScer\UAS.T:Ivir\HA1,T:wg under the control of Scer\GAL4109(2)80 in robo1 mutant animals partially rescues the mutant dendritic overgrowth phenotype from 58% to 18%.
Expression of roboScer\UAS.T:Ivir\HA1,T:wg under the control of Scer\GAL412.1 rescues the lch5 axon misprojection phenotype of robo4/robo4 embryos (only 5% of hemisegments show the mutant phenotype in the rescued embryos compared to 19% of hemisegments in the non-rescued embryos).
