A Database of Drosophila Genes & Genomes

FB2008_06, released July 3, 2008
 

Allele Dmel\sn3

General Information
SymbolDmel\sn3SpeciesD. melanogaster
NameFlyBase IDFBal0015773
Feature typealleleCreated / Updated2006-08-22/2006-08-22
Associated geneDmel\sn
Allele class
Mutagenspontaneous
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Allele class
Mutagen
Mapped Features and Mutations
Type
Symbol & Location
Additional Notes
References
 
 
 
 
Associated Sequence Data
DDBJ /
EMBL /
GenBank
DNA sequence
Protein sequence
Name
 
UniProtKB/Swiss-Prot
    UniProtKB/TrEMBL
      Progenitor genotype
      Nature of the lesion
      Statement
      Reference
      0.3 kb deletion in -0.9 to 0.0 kb; coordinates according to Roiha, Rubin and O'Hare (1988)
       
      0.3kb deletion from 1184bp to 1475bp of the wild-type sequence. This deletion is in the 5' end of the gene, and the coding region is intact.
      Assay mode
      Carried on aberration
      Cytology
      hide Phenotypic Data
      hide Phenotypic Class
      hide Phenotype Manifest In
      microchaeta & actin filament
      hide Detailed Description
      Statement
      Reference
      class 3 - female fertile with gnarled macrochaetae and kinky microchaetae
       
      Extreme bristle phenotype, female fertile.
      Extreme bristle phenotype.
      sn68/sn3 females have a sn mutant phenotype and are fertile.
      Bristles are gnarled due to disrupted actin filament bundles.
      Macrochaetae are bent, gnarled, twisted and considerably shorter than in wild-type flies. Microchaetae are often irregularly bent, and are shorter and less rigid than in wild-type flies. The ridges and valleys on the surface of the microchaetae are distorted. Actin bundles within the bristle cells are smaller and flatter than normal, and the filaments within them are disordered.
      Actin bundles are twisted in sn3 bristles.
      Mutation causes a severe denticle phenotype. Denticles tend to be smaller and have thinner hooks than wild-type denticles. They are also less orderly along each row and sometimes have a floppy appearance.
      Strong bristle phenotype.
      Actin bundles in the bristles of heterozygous flies are comparable in number and size to wild type and the area occupied by the filaments is not significantly different from wild type. The filaments are hexagonally packed. The bristles are the same length as in wild-type flies. Bristles of homozygotes are shorter than wild type.
      The arista laterals are shorter than normal and weakly curved in mutant flies.
      sn3 adults exhibit bent and twisted bristles of normal length. This phenotype is more pronounced in macrochaetes than microchaetes. Each macrochaete flute is not equally spaced nor equal in size and is twisted. Particularly in the lower half of the bristle, a honeycomb of short ridges 5-10υm in length is found, most of which is connected to a major longitudinal ridge. Overall, the ridges and valleys have a collective longitudinal orientation and continuous ridges of over 50υm in length and are common on most bristles, especially near the tip.
      The longitudinal actin bundles of wild-type bristle cells are composed of a hexagonally-packed array of actin filaments that form a triangular shape at the plasma membrane. sn3 mutants lack the fascin cross-bridges that usually form between actin filaments within a bundle. The longitudinal bundles of sn3 bristle cells contain fewer filaments than wild type; these filaments are liquid ordered not hexagonally-packed. These defects cause the bundles to form a rectangular shape that does not extend as far into the cytoplasm as the wild-type triangular bundle.
      The bristles of sn3 mutants are twisted; bristles can twist either to the right, to the left, or first in one direction and then the other. These mutant bristles have large gaps between flutes, reflecting abnormal distribution of the actin bundles. Apart from where twisting occurs, the curvature of sn3 bristles is similar to wild type. Additionally, sn3 mutant bristles lie flat over the surface of the thorax, instead of pointing away from the thorax, as in wild type.
      The cuticles of sn[3] mutants show thin, crooked, abnormal denticles.
      The wing hairs of sn[3] mutants show a 12-14% reduction in length compared to wild-type hairs. Few actin bundles are present in transverse or longitudinal sections taken through sn[3] hairs; rather, the actin filaments are present in an almost diffuse cortical layer.
      hide Interactions
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      hideOther
      Statement
      Reference
      hide Phenotype Manifest In
      hideEnhanced by
      Statement
      Reference
      sn3 has microchaeta & actin filament phenotype, enhanceable by f36a
      sn3 has macrochaeta phenotype, enhanceable by f36a
      sn3 has microchaeta phenotype, enhanceable by f36a
      sn3 has denticle phenotype, enhanceable by m1
      m1, sn3 has denticle phenotype, enhanceable by f36a
      f36a, m1, sn3 has denticle phenotype, enhanceable by shaV15
      f36a, m1, sn3 has denticle phenotype, enhanceable by WASp3
      hideNOT Enhanced by
      Statement
      Reference
      sn3 has arista phenotype, non-enhanceable by f36a
      hideNOT suppressed by
      Statement
      Reference
      sn3 has arista phenotype, non-suppressible by f36a
      sn3 has phenotype, non-suppressible by su(Hw)2
      hideEnhancer of
      Statement
      Reference
      sn3 is an enhancer of microchaeta & actin filament phenotype of f36a
      sn3 is an enhancer of microchaeta phenotype of f36a
      sn3 is an enhancer of macrochaeta phenotype of f36a
      sn3 is an enhancer of denticle phenotype of m1
      sn3 is an enhancer of denticle phenotype of f36a, m1
      hideNOT Enhancer of
      Statement
      Reference
      sn3 is a non-enhancer of arista phenotype of f36a
      hideNOT Suppressor of
      Statement
      Reference
      sn3 is a non-suppressor of arista phenotype of f36a
      hideOther
      Statement
      Reference
      hide Additional Comments
      hide Genetic Interactions
      Statement
      Reference
      Only 2% of postvertical bristles are split in sn3 f36a flies. The frequency of split bristles is increased by injection of cytochalasin D. Bristle elongation in sn3 f36a flies is more sensitive to vinblastine than in wild-type flies.
      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.
      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 bristles that are short, like f36a mutants, and twisted, like sn3 mutants.
      The denticles of m[1], sn[3] mutants show splitting in addition to the defects seen in either single mutant. sn[3], m[1], f[36a] triple mutants have small, highly misshapen denticles that are more affected than those of m[1], f[36a] or m[1], sn[3] double mutants. sn[3], m[1], f[36a]; sha[V15] and sn[3], m[1], f[36a]; WASp[3] quadruple mutants show further impairment to denticle formation compared to sn[3], m[1], f[36a] triple mutants, with mutants exhibiting regions of naked cuticle where denticles lie in wild-type animals. The dorsal hairs on the abdominal segments of sn[3], m[1], f[36a] triple mutants are severly reduced in size, and in some cases, hairs are abrogated leaving abnormal naked regions. This phenotype is more severe in sn[3], m[1], f[36a]; WASp[3] quadruple mutants and is even more severe in sn[3], m[1], f[36a]; sha[V15] mutants in which most dorsal hairs are absent, leaving naked cuticle.
      sn[3] f[36a] double mutants have ocellar bristles which are shorter and have a smaller volume than normal.
      hide Xenogenetic Interactions
      Statement
      Reference
      hide Complementation & Rescue Data
      Comments
      hide Stocks ( 90 )
      Bloomington
      113
      Kyoto
      101188
      105742
      101202
      105758
      hide Notes on Origin
      Discoverer
      Mohr, 11th June 1922.
      hide Synonyms & Secondary IDs ( 1 )
      Reported As
      Symbol Synonym
      Name Synonym
      Secondary FlyBase IDs
        hide References ( 28 )
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        hide Recent research papers ( 1 )
        Chanut-Delalande et al., 2006, PLoS Biol. 4(9):
        Shavenbaby couples patterning to epidermal cell shape control. [FBrf0191902]