FB2026_01 , released March 12, 2026
FB2026_01 , released March 12, 2026
Allele: Dmel\CycBS.hs
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General Information
Symbol
Dmel\CycBS.hs
Species
D. melanogaster
Name
FlyBase ID
FBal0065305
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Key Links
Transgenic product class
Nature of the Allele
Transgenic product class
Progenitor genotype
Carried in construct
Cytology
Description

A CycB cDNA lacking sequences encoding the destruction box is expressed under the control of a heat shock promoter.

A deleted form of CycB (lacking amino acids 3 to 47 and with a Gly residue as the second amino acid residue) is expressed under the control of an Hsp70 promoter. The deletion removes the "destruction box" and results in a stable CycB protein being produced.

Allele components
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Variant Molecular Consequences
Associated Sequence Data
DNA sequence
Protein sequence
 
Expression Data
Reporter Expression
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Marker for
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Human Disease Associations
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Disease-implicated variant(s)
 
Phenotypic Data
Phenotypic Class
Phenotype Manifest In
Detailed Description
Statement
Reference

Expression of CycBS.hs results in mitotic catastrophe in larval neuroblasts, including multinucleation and drastically increased cell diameter. Some loss of neuroblasts is seen.

When CycBS.hs is induced during the G2 phase of cycle 14, cytokinesis is not initiated.

In embryos expressing CycBS.hs, merotelic attachments are seen; i.e. kinetochore fibres are seen to extend from both poles to the pseudometaphase plate. Most but not all cells are fully arrested. Those that are not exhibit slow mitotic progress with a high frequency of chromosome segregation anomalies.

Heat shock expression of CycBS.hs produces embryos with cells arrested in an abnormal metaphase. Disjoined chromosomes can be seen scattered along the mitotic spindle. Progression through prophase and metaphase appears normal. Sister chromatids appear to disjoin and move toward opposite poles normally, albeit slowly. As the trailing tips of the longer chromosomes lose contact with their sisters, however, anaphase movement stops. After a pause, chromosomes move slowly along chaotic paths back to the midpoint of the spindle taking erratic and independant excursions towards the poles. The rate of this poleward movement varies from chromosome to chromosome. Excursions which are led by the kinetochore stop abruptly before reaching the pole, after which the chromosome drifts slowly back to the middle of the spindle in a movement not led by the kinetochore. Sometimes this gradual movement is interrupted by a sudden kinetochore led acceleration toward the opposite pole that typically carries the chromosome across the middle of the spindle and close to the other pole. Expression retards chromosome separation, slows chromosome movement and reduces the final extent of separation. Also the separation of the spindle poles during anaphase B is not seen.

S phase is not induced in embryos when cdc2AF.hs is co-expressed with CycBS.hs using heat shock.

External Data
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Additional Comments
Genetic Interactions
Statement
Reference

Co-induction of cdc2hs.PS and CycBS.hs leads to a more metaphase arrest than seen in CycAS.hs embryos alone.

Many cells of heatshocked embryos carrying cdc2AF.hs and CycBS.hs fail to delay mitosis after irradiation.

Expression of both CycAS.hs and CycBS.hs in embryos using heat shock results in most epidermal cells being arrested in mitosis 2 hours after the heat shock. No more than 2 centrosomes are seen at each spindle pole. All centriole pairs are disengaged and the centrioles are not associated with procentrioles.

Xenogenetic Interactions
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Complementation and Rescue Data
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Synonyms and Secondary IDs (2)
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    References (10)