Gene model reviewed during 5.48
Annotated transcripts do not represent all possible combinations of alternative exons and/or alternative promoters.
Gene model reviewed during 5.56
5.4 (northern blot)
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\ss using the Feature Mapper tool.
ss expression is observed in all bristle cells as well as in one photoreceptor cell (R7) in 60-80% of all ommatidia. Levels of ss vary considerably among R7 cells, ranging from very faint to very strong in 60-80% of R7 cells.
ss transcripts are expressed in embryos starting in stage 8 in a crescent just anterior to the cephalic furrow. As germ band extension proceeds, expression is observed in the maxillary, labial, mandibular, and antennal segments. This is followed by a patch of expression in the thoracic segments that corresponds to the leg anlage. Expression is also observed in the peripheral nervous system. ss transcripts are first detected in leg discs in 2nd instar larvae in a central ring that corresponds to the presumptive tarsal region. The ring fades by late third instar. ss is then expressed in a patch in the anterior-proximal part of the disc that gives rise to thoracic structures. Staining in the antennal disc is first detected in 2nd instar larvae and is located in an oval patch in the central portion of the disc. After disc eversion, the limits of the intense ss staining corresponds to the boundary between the second and third antennal segments. In late third instar, ss is expressed in the part of the disc corresponding to the maxillary palp anlage. In the wing disc, ss expression is in the region corresponding to the presumptive notum and the wing hinge. Expression is also observed in the haltere, genital, and labial discs and in the morphogenetic furrow in the eye disc. At pupariation, expression is observed in sensory organ precursor cells in most discs. At later stages, expression is seen in developing bristle cells but not in the associated socket cells.
ss protein is expressed in a subset of photoreceptor cells in the adult retina, in on/off manner. Expression in cells in the dorsal third region of the retina, relative to the equator is lower than in the other regions.
ss is expressed in the dorsal-proximal region of the 2nd thoracic and third thoracic leg discs. Expression is first detected in the mid third instar larval stage and persists at least until the early pupal stage. The distal region of the ss domain overlaps with the most proximal region of the al domain.
GBrowse - Visual display of RNA-Seq signalsView Dmel\ss in GBrowse 2
Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete
Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.
For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.
The ss gene product is incapable of high-affinity, specific binding of 3H-TCDD or 3H-BNF.
Loss of function alleles cause three major phenotypes: transformation of distal antenna to leg, deletion of distal leg, and reduction in the size of most bristles. Ectopic expression causes transformation of the maxillary palp and distal leg to distal antenna, and induces formation of ectopic antenna in the rostral membrane.
ss plays a central role in defining the distal regions of both the antenna and the leg. Loss of function phenotypes suggest that ss played a central role in the evolution of distal structures in arthropod limbs.
Mutants do not exhibit defects in the denticle belt of hairs of the larvae.
Results suggests that ss interacts with genes of homeotic complexes: ss gene is capable of repressing the effect of ANTC and BXC gene products on the formation of distal structure of the antennae and leg.
Varied sensitivities of the antenna-to-leg transformation are found both spatially and temporally.
Mutations at the spineless locus display three different phenotypes: (1) The spineless phenotype is characterized by the reduction in size of all bristles; (2) the aristapedia phenotype corresponds to the transformation of distal antennal segments, specifically the arista and the distal portion of the third antennal segment, into distal mesothoracic leg segments, i.e., tarsal segments; and (3) leg-segment fusion manifested as fusion of tarsal segments on all eight legs. Expression of these phenotypes varies among alleles. Some alleles show only the spineless phenotype. Aristapedia alleles, symbolized ssa, vary in expression; weak alleles show a swelling of the third antennal joint and rudimentary tarsal transformation of the base of the arista; as expression becomes more extreme, more tarsal joints are formed until in the most extreme alleles four tarsal segments and terminal claws are formed. Tarsal fusions are characteristic of extreme aristapedia alleles.
Effects of ss mutations on geotaxis measured in a Hirsch-type geotaxis maze: alleles of the "aristapedia" type show extremely positive geotaxis.
Homeotic tissue does not conform to developmental compartment boundaries; therefore, ss does not qualify as a selector gene.