Ubx1/Ubx9.22 transheterozygous embryos show a significant increase in the proportion of mitotic neuroblast daughter cells, but not of mitotic neuroblasts, only in the A1 ventral nerve cord segment, as compared to controls.
Homozygous clones in the posterior peripodial membrane cells of the wing disc have a wild-type cell shape.
Heterozygotes show a slight enlargement of the capitellum and occasionally one or two bristles are seen on the haltere.
The DA3 muscle pattern forms normally in Ubx1 embryos.
Epithelial cells within Ubx1 clones are appropriately positioned within the haltere disc epithelium and do not show any obvious change in cell shape or size.
Mitotic clones of Ubx1 and their wild-type twin spots respect compartmental boundaries.
Single cell class IV dendrite arborisation (da) neuron clones that are homozygous for Ubx1 show no significant defects in dendrite development.
Ubx1/+ flies show a mild haltere-to-wing transformation as the capitellum of the haltere produces between two and five wing margin-type sensory bristles.
Ubx1 flies show a haltere to wing transformation.
Ubx1 mutants do not show any thoracic phenotypes.
Mutant embryos show normal somatic gonadal precursor (SGP) specification, gonad coalescence and sexually dimorphic male-specific SGP behaviour.
Heterozygotes show a very weak transformation of haltere to wing, as indicated by an increase in haltere size and the development of a few wing-type marginal bristles.
When Ubx1 clones are made in the legs, a significant reduction in the T3 femur and basitarsus. The magnitude of the reduction in femur length is independent of the location of the clone in the anterior or posterior compartment and also independent of the size of the clone. With a few exceptions, clones on the basitarsus cause a similar reduction on basitarsus length. This non-autonomous reduction in length does not propagate across leg segments. T3 femurs are reduced in length, on average, to approximately the length of T2 legs of the same fly. In contrast the T3 basitarsi are reduced to a length approximately 7.8% shorter than the T2 legs. In these clones the cell area is autonomously reduced by 16.6%, implying the cell diameter is reduced by about 8.7%. This is double the observed reduction in leg length of 4.2%. These clones have a weak effect on the width of the femur, posterior clones have a stronger effect on leg width than anterior ones. However this reduction does not cause a reduction down to the width of T2 legs. Loss of Ubx in clones in the posterior and most of the anterior compartment of the T3 basitarsus have no significant effect on their width. Clones in the most ventral cells in the anterior compartment of the basitarsus do cause a large increase in the width of the basitarsus and the production of an ectopic row of bristles between rows 1 and 8. In every leg that displays ectopic bristles the basitarsus is swollen to 16-74% greater than normal width, whereas all other clones combined show a range in basitarsal width -10 +/- 14%. This basitarsal widening is associated with a more extreme reduction in lengthy than found in other legs carrying clones, suggesting that the swelling does not involve extra growth. However, the swelling causes the middle of the basitarsus to swell more than ends, so he change in length decreases at a rate somewhat smaller than the change in width. Overall, there is a weak correlation between the reduction in the number of bristles in rows and the magnitude of the reduction in leg length for legs with Ubx1 clones. However, different bristle rows display different responses to these clones. In rows 2, 4 and 78 clones cause an autonomous reduction in bristle number of about 14%, about the same average length reduction of about 15% for basitarsi carrying clones. however the other rows do not display a significant reduction of bristle number. In addition, non-autonomous effects of clones in some positions on bristle number in adjoining rows. The most striking effect is seen in row 1, when a clone is found in row 8. In this case, bristle number is reduced in row 1 by 16%. In contrast, when a clone is found anywhere else in the basitarsus except row 1 and 8, row 1 shows no significant reduction in bristle number.
Homozygous clones induced up to 22-16 hours before puparium formation can give rise to sternopleural macrochaetae on segment T3. Homozygous clones generated after the first cell division in the sternopleural proneural cluster can give rise to sternopleural macrochaetae on T3. Homozygous clones generated in the apical bristle precursors from the second-order stage give rise to bristle shaft and socket on the third leg. Clone induction 0-6 hours before puparium formation can result in the development of apical bristles on T3. Homozygous clones in the preapical precursors on T3 result in the formation of a bristle with a stout shaft resembling that of the preapical bristle on T2. 1.4% of heterozygous flies develop an apical bristle on the T3 leg.
Heterozygous females show a significant decrease in the level of 7,11-diene cuticular hydrocarbons compared to wild-type females.
When heterozygous with UbxHC71-1.HC166D.Dup.Rec.ry+ the notum reduction phenotype is much more penetrant and severe. These animals also show an enlargement of the haltere, with anterior bristles, characteristic of a weak bx transformation.
The addition of the polyamide P31 enhances the A6 to A5 phenotypes seen in bwD, Ubx1 flies. Sex combs are reduced, halteres are partially transformed into wing-like structures. Viability is reduced, development is often halted before pupation. P31 has no effect flies with Ubx1 alone.
Homozygous clones in the haltere induced at 6 hours BPF do not result in any abnormalities in the final cuticle. Homozygous clones in the haltere induced 24-48 hours before puparium formation (BPF) produce thicker, longer and more widely spaced hairs than the neighbouring haltere cells, suggesting that they are partially transformed to the wing cell type. Homozygous clones induces 6 hours after puparium formation transform the haltere sensillum to resemble that in the wing.
Clones generated on the haltere margin display wing margin bristles, while clones in the capitellum sort out from the surrounding cells and remain inside the haltere. Some 'rescued' clones in the capitellum remain on the surface and differentiate wing trichomes: these occur when the haltere also carries a clone on the margin, which is behaving as a wing D/V organizer. Clones induced in a ft8 background, where larval life is extended and imaginal discs undergo extra rounds of division, show non-autonomy of the haltere to wing transformation.
Hemizygous larvae have both a dorsal and ventral disc bud in A1, along with a remaining posterior dorsal histoblast nest. The anterior dorsal histoblast nests are sometimes inverted in flies transheterozygous for Ubx1 and other Ubx alleles.
Does not affect the frequency of the trx bithorax-variegated phenotype in heterozygous combination with Df(3R)red-P52.
Homozygous Ubx1 mutants eliminate wg expression but the effect of Ubx and dpp is indirect.
Ubx1/Ubxbx-34e flies have very little transformed dorsal metanotum.
Transheterozygotes with Ubxbx-8 and Ubxbx-34e show an enhancement of the bx phenotype when in combination with E(bx)2. Haltere to winglike and metanotum to mesonotumlike transformations are enhanced. Ubxpbx-1 and Ubxbxd-1 show haltere to winglike transformation enhancement.
In homozygotes the anterior first abdominal segment is transformed into mesothorax.
Homozygous clones induced 8 hours after fertilization show transformation of the dorsal and ventral metathorax, haltere and third leg into wing and second leg respectively. Earlier clone induction causes transformation of the posterior compartments of both the second and third legs into the posterior compartment of the first leg. Scr13A Ubx1 clones induced at the blastoderm stage or larval stage is the additive phenotype of Scr13A and Ubx1 clones, prothorax is transformed to metathorax. The phenotype of triply mutant clones AntpNs-rvC3 ScrC1 Ubx1 at the blastoderm stage is the additive phenotype of AntpNs-rvC3 and Scr13A Ubx1 clones, portions of all three legs are transformed to antennae, clones in the haltere and metanotum form wing and mesonotum structures and transformation of labial palps of the proboscis into maxillary palps. The phenotype of AntpNs-rvC3 Ubx1 clones induced in the head, pro- and mesothorax during embryonic and larval development are indistinguishable from AntpNs-rvC3 ScrC1 Ubx1 clones.
The frequency of variegated bithorax transformations seen in Df(3R)red-P52 heterozygotes is not increased in flies also heterozygous for Ubx1.
Halteres of heterozygote about twice normal volume, characteristically with one or more hairs on anterior surface of swollen apical segment, or capitellum, of the haltere. No overlap with wild type and little variability; accurate scoring takes practice. Homozygous larva has, in addition to normally present mesothoracic pair of spiracles, both a metathoracic and a first abdominal spiracle pair.