axon & dorsal cluster neuron | somatic clone
ventral adult lateral neuron & commissure
Pupal retina constituting almost entirely of somatic clones (induced specifically in the eye) triple homozygous for Rac2Δ,Rac1J11,MtlΔ do not show any extra cone cells or primary pigment cells, only extra inter-ommatidial cells are observed.
The presence of Rac2Δ/+, Rac1J11/+ and MtlΔ/+ mutations fails to suppress the reduction of differentiation seen in eye-antennal disc clones expressing both RhoGEF2RE.Scer\UAS and Ras85DG12V.Scer\UAS under the control of Scer\GAL4tub.PU, and also fails to suppress the developmental delay shown by larvae containing these clones.
Co-expression of Ced-12Scer\UAS.cGa and mbcScer\UAS.cBa via Scer\GAL4Mef2.PR results in prevalent myoblast fusion, muscle attachment, and tendon cell identity phenotypes in embryos. The muscle attachment and tendon cell phenotypes are largely rescued in a Rac1J11/+, Rac2Δ/+ background.
Myoblast fusion is defective in Rac1J11 Rac2Δ double mutant embryos, although some fusion does occur. Binucleate muscle precursors that have undergone a single fusion event between a founder cell and a fusion competent myoblast are seen in the mutant embryos as follows: DA1 (64.2% of segments), DO1 (68.3% of segments), LO1 (26.3% of segments), VT1 (66.7%) of segments.
A mild, though not significant enhancement of the ommatidium-phenotype resulting from the co-expression of Arf51FGD13822 with Dcr-2Scer\UAS.cDa under the control of Scer\GAL4GMR.PF is observed in a Rac1J11, Rac2Δ, MtlΔ heterozygous background.
No rhabdomeric defect is seen at the base of the rhabdomere at eclosion in flies in which the eyes are triply mutant for Rac1J11 Rac2Δ MtlΔ, although there is an axon guidance defect in the optic lobe.
prtpΔ1/+ ; Rac1J11 Rac2Δ/+ triple heterozygotes show a reduced level of phagocytosis in embryonic hemocytes (neither prtpΔ1/+ single heterozygotes nor Rac1J11 Rac2Δ/+ double heterozygotes show a reduction in phagocytosis compared to wild type).
A Rac1J11 Rac2Δ MtlΔ heterozygous background enhances the patterning defects found in Scer\GAL4GMR.PF>cindrdsRNA.PC.PD.Scer\UAS mutants. The mean interommatidial precursor cell number and the number of cone and/or 1[o] cell errors is increased in these double mutants.
The Scer\GAL4elav-C155/DAAMC.Scer\UAS.P\T gain-of-function phenotype (i.e the appearance of thicker commissures and nerve roots) is not affected by Rac1 gene dose (i.e. a Rac1J11/+ or Rac1J11/Rac1J10 background), a Rac1J11, Rac2Δ background or a Rac1J10, Rac2Δ, MtlΔ background.
A Rac1J11 background enhances the zygotic DAAMEx68 CNS phenotype, with the severity of the phenotype correlating with the number of Rac1 copies removed. A DAAMEx68 heterozygous background strongly enhances the axonal growth defects exhibited by Rac1J11 mutants.
Rac1J11, Rac2Δ, MtlΔ triple mutant clones in the eye result in a low frequency (approximately 5%) of planar polarity defects (such as achiral or misrotated ommatidia). Cdc425, Rac1J11, Rac2Δ, MtlΔ quadruple mutant clones in the eye result in a higher frequency of (14.2%) of planar polarity defects.
Rac1J11 Rac2Δ MtlΔ triple mutant myoblasts show enlarged foci, as well as increased numbers of actin foci. Enlarged foci are seen in these mutants from the earliest stages of fusion and foci persist after fusion would be complete in wild-type.
The salivary gland defects seen in Rac1J11 embryos are enhanced in Rac1J11 Rac2Δ mutants; more cells remain at the ventral surface of the embryo and the gland fails to migrate posteriorly. In addition, the lumen of the salivary gland is disrupted, with breaks in the lumen being seen during posterior migration of the gland, and cyst-like lumena being seen in the mature gland.
shi2 Rac1J11 Rac2Δ MtlΔ heterozygous embryos form normal salivary glands at the permissive temperature of 25[o]C. However, at the restrictive temperature of 30[o]C, posterior migration of the salivary gland is disrupted.
The Rac1J11 mutation fails to modify the cv-cM62 phenotype in the Malpighian tubules. Dorsal closure defects occur in 82% of Rac1J11, Rac2Δ double mutant embryos. If these mutants also carry the cv-cM62 mutation , 37 % of these embryos are rescued. In cv-cM62, Rac1J11, Rac2Δ triple mutants, the posterior spiracle phenotype is enhanced compared to cv-cM62 mutants. Posterior spiracle phenotypes are seen in Rac1J11, Rac2Δ embryos, but with low penetrance.
In Rac1J11; Rac2Δ double homozygous embryos, rearrangement of tubule cells to produce elongated, 2 cell wide tubules is partially disrupted and tubule migration is defective. The anterior tubules follow an erratic path, doubling back on themselves to form loops and knots.
The penetrance of the LNv ectopic branch phenotype is increased to 100% and the posterior tract defasciculation phenotype is increased to 93% when Fmr1Δ113M/+ flies are also heterozygous for Rac1J11. Likewise, the LNv ectopic branch phenotype is increased to 100% and the posterior tract defasciculation phenotype is increased to 93% when Rac1J11/+ flies are also heterozygous for Fmr1Δ113M.
One hour after laser-induced wounding, approximately half the number of hemocytes are recruited to the wound in embryos triply mutant for Rac1J11, Rac2Δ and MtlΔ compared to wild type embryos. Hemocytes that are recruited in the triple mutant embryos have significantly reduced lamellar protrusions.
Germ line clones of the Rac1J11 Rac2Δ MtlΔ triple mutant fail to produce embryos. Zygotic Rac1J11 Rac2Δ MtlΔ triple mutants, that have wild-type maternal contribution of Rac1, survive beyond early dorsal closure, but still show 100% embryonic lethality. These embryos achieve dorsal closure, but show puckering along the dorsal side. The dorsal hole becomes a long slit-like shape as it closes in the triple mutants, while the hole has an oval shape in wild-type embryos. Although amnioserosa cells are significantly larger in the mutants than in wild type, these cells are able to contract at a similar rate to wild type. The leading edge of zygotic Rac1J11 Rac2Δ MtlΔ triple mutants is disorganized and, unlike in wild-type embryos, is not taut. Many of the triple mutant leading edge cells are polygonal in shape, instead of being dorsally-ventrally elongated, like in wild type. Some of the cells in the mutant edge assemble the actin cable and actin projections, while other cells fail to do so. Leaky expression of hepCA.Scer\UAS, with no GAL4 driver, partially rescues the lethality and dorsal puckering phenotype of Rac1J11 Rac2Δ MtlΔ triple mutants.
Rac1J11/+ has very little effect on the mutant wing phenotype caused by expression of LIMK1Scer\UAS.cCa under the control of Scer\GAL4en-e16E (the % of wings with normal morphology at 18oC is 23% compared to 9% for control flies expressing LIMK1Scer\UAS.cCa under the control of Scer\GAL4en-e16E in an otherwise wild-type background). The frequency of the malformed leg phenotype seen in Sb63b/+ heterozygotes (8%) is not increased if the flies are also heterozygous for Rac1J11/+ (3%). The frequency of the malformed leg phenotype seen in Sb70/+ heterozygotes (7%) is not increased if the flies are also heterozygous for Rac1J11/+ (2%). The frequency of the malformed leg phenotype seen in br1/Y males (1%) is not increased if the flies are also heterozygous for Rac1J11/+ (0%).
Rac1J11, Rac2Δ mutant embryos exhibit arrested ganglionic branches (GBs), and GBs turning prematurely away from the midline. robo4 partially suppresses the ganglionic branch phenotype seen in Rac1J11, Rac2Δ embryos.
In a subset of the epidermal cells of stage 15 Rac1J11, Rac2Δ double homozygous embryos, the distinction between apical and basolateral domains is compromised. At stage 16 the columnar epithelial cells are shorter than wild-type and parts of the epidermis become multilayered. Reducing the maternal and zygotic gene dosage of Rac1J11 and Rac2Δ together produces embryos exhibiting tracheal defects of increasing severity: the mildest phenotype is a mis-routing of the dorsal branches toward the anteroposterior direction, whereas more severely affected embryos also exhibit truncations of the dorsal trunk. Order of severity: maternal(M) +/+ zygotic(Z) +/- =WT. M -/+ Z +/+ < M -/+, Z -/+ < M +/-, Z -/-. The proportion of M -/+, Z -/+ embryos with severely affected tracheal systems is enhanceable by heterozygosity for bnl00857, btlΔOh10, or stumps09904b.
In a subset of the epidermis of stage 15 Rac1J11, Rac2Δ double homozygous embryos the distinction between apical and basolateral domains is compromised. At stage 16 the columnar epithelial cells are shorter than wild-type and parts of the epidermis become multilayered. Reducing the maternal and zygotic gene dosage of Rac1J11 and Rac2Δ together produces embryos exhibiting tracheal defects of increasing severity: The mildest phenotype is a misrouting of the dorsal branches toward the anteroposterior direction, whereas more severely effected embryos also exhibit truncations of the dorsal trunk. Order of severity: maternal(M) +/+ zygotic(Z) +/- =WT. M -/+ Z +/+ < M -/+, Z -/+ < M +/-, Z -/-. The proportion of M -/+, Z -/+ embryos with severely effected tracheal systems is enhanceable by heterozygosity for bnl00857, btlΔOh10, or stumps09904b.
The combination of heterozygous sli2 and Rac1J11 leads to an enhancement of the longitudinal axon ectopic midline crossing defects. An average of 4.8 defects are seen per animal, and an average of 44% of segments have defects.
Rac1J11 Rac2Δ MtlΔ triple mutant clones in the wing and eye do not show planar cell polarity defects. Mosaic flies in which the eye is doubly mutant for Rac1J11 and Rac2Δ show mild defects in the projection pattern of photoreceptor cell axons. Mosaic flies in which the eye is triply mutant for MtlΔ, Rac1J11 and Rac2Δ show severe defects in the projection pattern of photoreceptor cell axons, showing a medulla bypass phenotype. Specification of photoreceptor cell fate appears to be normal.
55% of Rac1J11 Rac2Δ double mutant neuroblast clones show defective guidance. 55% of Rac1J11 Rac2Δ MtlΔ single-cell γ neuron clones in the mushroom body show axon-stalling defects, mostly at the peduncle. There is a significant reduction in total dendritic length and number of dendritic segments per neuron compared to wild type. Mushroom body axon growth defects in single-cell Rac1J11 Rac2Δ MtlΔ γ neuron clones are largely rescued by expression of Rac1Scer\UAS.T:Hsap\MYC or Rac1Y40C.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4OK107. Mushroom body axon growth defects in single-cell Rac1J11 Rac2Δ MtlΔ γ neuron clones are not rescued by expression of Rac1F37A.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4OK107. 81% of axons in Rac1J11 Rac2Δ mushroom body clones show mutant phenotypes, predominantly guidance (55%) and branching (24%) defects. Expression of Rac1Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4OK107 markedly rescues these defects. Expression of Rac1Y40C.Scer\UAS.T:Hsap\MYC under the control of Scer\GAL4OK107 does not reduce the total percentage of axonal defects in Rac1J11 Rac2Δ mushroom body clones, but results in a marked shift in the distribution of defects, with most showing branching (45%) rather than guidance (31%) defects. Analysis of Rac1J11 Rac2Δ mushroom body clones indicates cell non-autonomous effects in axon guidance and branching caused by defective "Rac" activity.
Expression of Rac1Scer\UAS.cLa under the control of Scer\GAL4sns.PK strongly rescues the myoblast fusion defects of Rac1J11 Rac2Δ double mutant embryos, resulting in a near normal somatic muscle pattern. In contrast, expression of Rac1Scer\UAS.cLa under the control of Scer\GAL4kirre-rP298 rescues the myoblast fusion defects of Rac1J11 Rac2Δ double mutant embryos much less efficiently.