dpphr56 heterozygous females show the expected mating-induced increase in germline stem cells in the germarium.
dppd5/dpphr56 mutants show abnormal wing phenotypes and reduced viability.
7-day old dpphr56/+ germaria have normal numbers of germline stem cells (GSCs), but at 63-days old, these germaria have significantly lower GSC numbers compared to controls - most have only one or no GSCs. 35-day old and 63-day old heterozygous germaria also contain significantly fewer cysts than controls, although cap cells are maintained at normal numbers.
dppd5/dpphr56 flies show reductions in wing vein spacing and loss of wing veins.
The wings of dppd5/dpphr56 transheterozygotes show a truncation of the L2 vein (40% penetrance), reduction of the L4-L5 intervein (48% penetrance) and partial fusion of the L4-L5 intervein (52% penetrance).
The wing pouch of dppd12/dpphr56 wing discs is reduced to essentially a dorsal/ventral margin with no detectable vein primordia.
When single cell dpphr4/dpphr56 clones are made in the wing imaginal disc, cytonemes in the wing primordium are affected. At the non-permissive temperature (29oC) cytonemes emanating from cells at the lateral flanks of discs do not orient themselves towards the anterior posterior organiser (as those see in wild-type do). Cytonemes in these discs are also more numerous than in wild-type, and unlike in the wild-type, are sometimes seen to be bent, curved or crossing over each other. These effects are not observed if mutant larvae are heatshocked and returned to permissive temperatures.
In females carrying the temperature sensitive allelic combination dpphr56/dppe90 raised at 18oC and shifted to 29oC (the non-permissive temperature) for 10, germaria are agametic but contain only slightly less follicle cells than control agametic germaria (bamhs.PO 10 days after two 2 hour heat shock treatments.
dppe90/dpphr56 or dpphr4/dpphr56 males raised at 18oC to eclosion and then shifted to 29oC, show no significant loss of germline stem cells after 1 week.
In mutant embryos, the dorsal medial head epidermis fails to develop as reflected by the presence of a continuous optic placode across the dorsal midline. Cell death is decreased in the dorsal midline region of the embryo.
dpphr27/dpphr56 males that have been raised at 18oC and then shifted to the restrictive temperature of 29oC upon eclosion do not have any overt morphological abnormalities in the testes after 7 days at 29oC and the testes contain germ cells in all stages and in quantities indistinguishable from that of controls.
dppd5/dpphr56 flies show loss of wing veins L2 and L4 and loss of the intervein region between veins L4 and L5.
Heterozygotes show a mild reduction in size compared to wild type.
dpphr56/dppd5 flies occasionally show notching of the wing margin.
dppd8/dpphr56 flies show a small notching of the wing tip in less than 10% of cases.
Eggs laid by dpphr56/+ show 99.1% wild type dorsal appendages, 0.7% broad dorsal appendages and normal egg length and 0.2% abnormal dorsal appendages with short egg length.
Females carrying temperature sensitive combinations dppe90/dpphr56 or dpphr4/dpphr56 after shifting to the restrictive temperature for one week show 40-50% of germaria that are significantly smaller than wild type. The effect is more pronounced in older females. Stem cell number is reduced, stem cells have differentiated into cysts. Some effect on egg chamber budding is seen.
Eye discs from dpphr4/dpphr56 larvae grown at 29oC for 48 hrs show several phenotypes including failure of retinal differentiation or partial ommatidial differentiation, ommatidia are retricted to the posterior part of the disc and absent from the lateral margins. Occasionally eye discs show normal size and morphology. These eye discs show anterior-most ommatidia that are abnormal mature in comparison to wild type ommatidia at similar positions. Also, cell death is observed ahead of the differentiated region. Surviving adults show slightly roughened eyes that are reduced along the anterior-posterior axis, consistent with a failure of normal morphgenetic progression.
At 25oC, dppe87/dpphr56 animals die, while at 18oC many survive to adulthood. Surviving females shifted to 25oC lay eggs of which some show anterior eggshell defects: reduced opercula, slightly reduced dorsal appendages and some show reduced egg length. The operculum defects are often accompanied by small protrusions of ectopic eggshell extending off the anterior pole, and more rarely malformations of the micropyle.
Embryos show cuticular holes, disorganization of the head skeleton, internalization of the seventh and eighth abdominal segments and the filzkorper and a thoracic constriction. A significant percentage of surviving transheterozygotes between dpphr56 and dpphr4 or dpphr27 have a split notum. dpphr56 shows a temperature sensitive embryonic lethality: percentage embryonic lethality drops from 26% at 25oC to 5% at 18oC. Temperature sensitivity is evident in denticle pattern as well as survival. dpphr56 is differentially temperature sensitive to embryonic and imaginal requirements for dpp. Outcrossed lines retain lethality at 18oC, though this lethality acts at the pharate/pupal adult stage. Homozygotes exhibit canonical dpp disc phenotypes, with small roughened eyes, reduced wings and short truncated legs. dpphr56 is affecting a dpp function that is required differentially in embryonic and imaginal tissue.
Survival of heterozygotes is reduced if also heterozygous for certain alleles of tld.
Clonal analysis in the developing eye (using the FLP/FRT system) revealed nonautonomous phenotypes with large clones showing posterior-lateral eye parts missing.
Dominant lethality less than 50%. Homozygous and transheterozygous embryos were examined with respect to 25 cuticular markers, results demonstrate a graded requirement for dpp along the dorso-ventral axis.
Fully rescued to adulthood by two wild type copies of dpp.
Trans-heterozygotes display normal dorsal ventral polarity but show defects in head and cauda formation.