Type II neuroblast lineage MARCM clones mutant for Ras85DΔC40B
do not display any significant changes in the clone morphology, size or the number of progenitor cells it contains compared to wild-type clones.
Although the initial growth of Ras85DΔC40B
mutant intestinal stem cell clones is normal, their long-term proliferation is severely compromised. These clones do not grow even after the flies have recovered from Pseudomonas entomophila infection.
6 days after clone induction, 100% of testes carry one or more marked homozygous CPC clones, with an average of 3.4 marked homozygous CPCs per testis (compared to 92% of testes carrying one or more marked wild-type CPC clones, with an average of 1.1 marked wild-type CPCs per testis).
mutant eye disc clones show defects in ommatidium development. Gaps and partially-formed rosettes are observed within the ommatidial array.
mutant adult Malpighian tubule clones only a few differentiated renalcytes (RCs) are detected, reduced in number compared to control clones.
mutant adult midgut progenitor cells fail to proliferate during larval development.
Homozygous clones in the eye disc are much smaller than their wild-type twin spots.
Minute clones in the eye disc fail to form the arcs and rosettes of cells in the morphogenetic furrow that are seen in wild-type eye discs.
Larval eye discs containing Ras85DΔC40B
clones show a higher level of cell death than controls.
Clones of Ras85DΔC40B
generated in the developing eye are aberrantly small.
Oocyte polarity and apical-basal polarity of posterior follicle cells (PFCs) is disrupted in Ras85DΔC40B
mutant PFC clones.
The initiation of mesoderm spreading is unaffected in homozygous embryos derived from homozygous female germline clones.
Embryos derived from homozygous Ras85DΔC40B
female germ line clones have 20-30% fewer pole cells by the cellularization stage, due to mitotic defects, when compared with wild-type embryos. These mutant embryos exhibit defective gastrulation and lack the posterior midgut primordium. The majority of pole cells are unable to enter the embryo at gastrulation and those that do enter the embryo appear abnormal in both directed migration and aggregation, leading to their random scattering in the embryonic cavity. Analysis of pole cell transplantations, in which pole cells from cellularization stage embryos derived from Ras85DΔC40B
female germ line clones and wild-type fathers are transplanted into wild-type embryos shows that no Ras85DΔC40B
pole cells are ever found in the gonad of the transplanted embryo but migrate to ectopic locations. These Ras85DΔC40B
mutant pole cells disappear in late stage embryos, possibly due to cell death.
mutant somatic clones in the 3rd instar eye disc, photoreceptors R2-R5 fail to undergo or differentiation. Within Ras85DΔC40B
mutant somatic clones there is a failure of G1 arrest in the furrow: all cells except R8s re-enter the cell cycle. However, none of these cells progress past G2.
Homozygous clones in the follicle cells are smaller than control clones and are detected at a lower frequency 6 days after clone induction. Large follicle stem cell clones are not recovered 10 days after clone induction. 16% of stage 14 eggshells laid by mosaic females (containing homozygous follicle cell clones) 5-7 days after clone induction have dorsal appendage defects. The defects include complete lack of dorsal appendages (15%), a small "nub" of extra chorion material next to two normal dorsal appendages (4.5%), short dorsal appendages (11%), fragmented dorsal appendages (11%), one dorsal appendage replaced by a nub of chorion material (42%), both dorsal appendages replaced by a nub of chorion material (12%) and fragmented dorsal appendages plus an extra nub of material (4.5%). Mutant cells are not found amongst the migrating follicle cells that give rise to dorsal appendages. Aberrant nubs and fragments of dorsal appendages are not made by mutant cells, but by wild-type cells adjacent to mutant clones. Egg chambers with dorsal anterior mutant clones show gross disruption of the apical morphology of the dorsal appendage primordia at stage 12.
Homozygous somatic clones in the wing, autonomously prevent wing vein formation.
Homozygous embryos show loss of VA2 muscle precursor cells (only 9% of hemisegments contain VA2 precursor cells).
Excess R8 cell precursors are seen in homozygous clones in the eye disc.
A gradual decline over time in the number of homozygous clones present compared to wild-type sister clones is seen in imaginal discs. There is also a decline in the area of the surviving homozygous clones compared to wild-type clones. The homozygous clones contain many pyknotic nuclei. Relatively large homozygous clones containing 40-80 cells are seen even 72 hours after induction, but at a low frequency. Homozygous clones (which are RpS3+
) induced in discs which are RpS3-
/+ have increased survival rates and are larger than homozygous clones induced in a wild-type background.
Embryos derived from homozygous female germline clones develop abdominal segment A8 in 20.3% of cases and filzkorper in 0.4% of cases.