|Feature type||allele||Associated gene||Dmel\f|
|Allele class||amorphic allele - genetic evidence|
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|Nature of the Allele|
|Mutations Mapped to the Genome|
|Associated Sequence Data|
|Nature of the lesion|
Insertion of a full length springer element at nucleotide 16513 within the coding region of the PRD repeat in the opposite orientation to the f gene.
Single springer insert in the third exon.
A member of the right-hand group of alleles. Contains a 3.0 kb insertion 2.5 kb to the right of the reference SalI site (McLachlan, 1986).
|Caused by insertion|
|Phenotype Manifest In|
macrochaeta & actin filament
The wing hairs of f36a mutants show a 12-14% reduction in length compared to wild-type hairs. The f36a mutant hairs are less rigid than in wild type and appear to lie on the surface of the wing.
Bristles are shorter and thicker in f36a mutant flies than in wild type. These mutant bristles lie flat over the surface of the thorax, instead of pointing away from the thorax, as in wild type.
In f36a mutants, the adult bristles are on average only 50% as long as the wild-type. Most are twisted or deformed and in some cases exhibit forked tips. These bristles tend to be larger in diameter than in wild-type or sn3 mutants. Some show an irregular longitudinal fluting along a portion of their length, although the ridges are not evenly spaced. In other regions, large numbers of short ridges, appearing at all angles relative to the longitudinal axis are found. Some of these short (2-10υm in length) ridges connect to other ridges at the tapered tips.
Longitudinal actin bundles in the bristle cells of f36a mutants are flattened against the plasma membrane in an aberrant rectangular shape. The bundles lack the f cross-linker and contain fewer filaments than in wild type. However, the packing of the mutant filaments is hexagonal, like in wild type.
The arista laterals are shorter than normal and weakly curved in mutant flies.
Actin bundles in the bristles of homozygous flies are tiny compared to wild type, the largest containing only 50 filaments compared to the wild-type 500-700 filaments per bundle. The filament bundles occupy only about one third of the area occupied by wild-type bundles. The bristles are approximately 56% the length of wild-type bristles. Although there are patches in the actin bundles of heterozygous bristles where the filaments are hexagonally packed, most of the filaments show more diffuse packing. The filament bundles occupy about two thirds of the area occupied by wild-type bundles. The bristles are similar in length to wild-type bristles.
The number of membrane-associated actin bundles in homozygous newly emerged bristles is higher than in wild-type flies. Most of these bundles fail to aggregate and subsequently disappear. The diameter of the actin bundles at the tip of homozygous fully emerged bristles is smaller than in wild-type. Actin bundles in heterozygous bristles are more variable in thickness than in wild-type, with many appearing somewhat swollen and less compact than in wild-type flies. The number of actin filaments per bundle is always less than in wild-type bundles of the same diameter.
Larvae exhibit an intermediate bristle phenotype within the denticles of all rows. Dorsal surface of the first abdominal segment instead of being long are short, fat, often spindle shaped and apparently branched, fused or duplicated laterally.
Macrochaetae are very short and malformed. Microchaetae are also shorter than normal, and in some cases their bases just outside the socket are enlarged. Trichomes are often forked. Actin bundles within the bristle cells are much smaller than normal.
Large bristles are twisted, gnarled and sometimes branched. In 36hr pupae, wild type and mutant are similar, bristles are embedded in extracellular matrix and filled with microtubules. By 40hrs, the fiber bundles that in wild type are formed at intervals around the perimeter of the bristle are absent in mutants. The thickening of the outside edge of the bristle, in positions coincident with the fiber bundles in wild type, still occurs in mutants.
The frequency of yunspecified-f36a clones produced by mitotic recombination during larval growth is greater in flies derived from crosses of yunspecified f36a D.melanogaster females to D.melanogaster males than in flies derived from crosses of yunspecified f36a D.melanogaster females to D.simulans males.
|Phenotype Manifest In|
|NOT Enhanced by|
|NOT suppressed by|
|NOT Enhancer of|
|NOT Suppressor of|
The denticles of m1, f36a mutants show splitting in addition to the defects seen in either single mutant. sn3, m1, f36a triple mutants have small, highly misshapen denticles that are more affected than those of m1, f36a or m1, sn3 double mutants. sn3, m1, f36a; shaV15 and sn3, m1, f36a; WASp3 quadruple mutants show further impairment to denticle formation compared to sn3, m1, f36a triple mutants, with mutants exhibiting regions of naked cuticle where denticles lie in wild-type animals. The dorsal hairs on the abdominal segments of sn3, m1, f36a triple mutants are severly reduced in size, and in some cases, hairs are abrogated leaving abnormal naked regions. This phenotype is more severe in sn3, m1, f36a; WASp3 quadruple mutants and is even more severe in sn3, m1, f36a; shaV15 mutants in which most dorsal hairs are absent, leaving naked cuticle.
pixL17, f36a clones induced in the wing disc 27 hours before larval wandering rarely survive to the adult wing. Those that do display a strong reduction in cell number but not cell size.
sn3, f36a double mutants have bristles that are short, like f36a mutants, and twisted, like sn3 mutants.
In f36a sn3 double mutants, bristle ridges of length more than 10υm (45% of wild-type length) are not found. Instead, a variety of short ridges 3-10υm in length are found. Some of these are parallel to the longitudinal axis of the bristle, whereas others are perpendicular or oblique. These ridges are seldom connected to one another but terminate freely on the surface.
In f36a, sn3 double mutants, bristle cells contain tiny rafts of membrane-attached actin filament clusters, which consist of a monolayer of filament. This is a more extreme phenotype than that observed with either of the single mutants. When these f36a, sn3 mutant cells are treated with jasplakinolide, large clusters of actin filaments appear internally, most of which run parallel to the longitudinal axis of the bristle. These clusters have an irregular shape and have a liquid ordered packing of filaments, instead of wild-type hexagonal packing.
sn3 f36a double mutants have ocellar bristles which are shorter and have a smaller volume than normal.
The arista lateral phenotype of sn3 f36a double mutants is not substantially stronger than either single mutant. Double mutant arista laterals are thinner than wild type. At a low frequency, branched laterals are seen. The mutant laterals start to extend at the normal time, but their rate of extension is slower than normal.
|Complementation & Rescue Data|
|Partially rescued by|
|Stocks ( 52 )|
|Notes on Origin|
Ives, 27th Jan. 1936.
|External Crossreferences & Linkouts|
|Synonyms & Secondary IDs ( 1 )|
|Secondary FlyBase IDs|
|References ( 30 )|
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|List References by type|
|Recent research papers (0)|
|All research papers listed in FlyBase were published before 2011|