FlyBase Allele Report: Dmel\Top2[suo1]

General Information

Symbol

Dmel\Top2^suo1

Species

D. melanogaster

Name

FlyBase ID

FBal0177591

Feature type

allele

Associated gene

Dmel\Top2

Associated Insertion(s)

Carried in Construct

Key Links

Allele class

hypomorphic allele - molecular evidence

Mutagen

ethyl methanesulfonate

Nature of the Allele

Allele class

hypomorphic allele - molecular evidence

(Mengoli et al., 2014)

Mutagen

ethyl methanesulfonate

(Bucciarelli et al., 2003)

Progenitor genotype

Cytology

Description

No mutation has been found in any Top2 protein coding exon.

(Mengoli et al., 2014)

Mutations Mapped to the Genome

Curation Data

Type

Location

Additional Notes

References

Variant Molecular Consequences

Associated Sequence Data

DDBJ / EMBL / GenBank

DNA sequence

Protein sequence

UniProtKB/Swiss-Prot

UniProtKB/TrEMBL

Expression Data

Reporter Expression

Additional Information

Statement

Reference

Marker for

Reflects expression of

Reporter construct used in assay

Human Disease Associations

Disease Ontology (DO) Annotations

Models Based on Experimental Evidence ( 0 )

Disease

Evidence

References

Modifiers Based on Experimental Evidence ( 0 )

Disease

Interaction

References

Comments on Models/Modifiers Based on Experimental Evidence ( 0 )

Disease-implicated variant(s)

Phenotypic Data

Phenotypic Class

Phenotype Manifest In

chromatin | male (with Df(2L)Exel9043)

(Mengoli et al., 2014)

chromatin | male (with Top2^suo3)

(Mengoli et al., 2014)

chromosome

(Bucciarelli et al., 2003)

chromosome | male (with Top2^suo3)

(Mengoli et al., 2014)

chromosome | third instar larval stage

(Mengoli et al., 2014)

chromosome | third instar larval stage (with Df(2L)Exel9043)

(Mengoli et al., 2014)

chromosome | third instar larval stage (with Top2^suo3)

(Mengoli et al., 2014)

embryonic/larval salivary gland | larval stage | male (with Df(2L)Exel9043)

(Mengoli et al., 2014)

embryonic/larval salivary gland | larval stage | male (with Top2^suo3)

(Mengoli et al., 2014)

eye

(Yang et al., 2021)

larval brain | third instar larval stage

(Mengoli et al., 2014)

larval brain | third instar larval stage (with Df(2L)Exel9043)

(Mengoli et al., 2014)

larval brain | third instar larval stage (with Top2^suo3)

(Mengoli et al., 2014)

metaphase & condensed nuclear chromosome

(Bucciarelli et al., 2003)

mitotic metaphase

(Bucciarelli et al., 2003)

polytene chromosome | larval stage | male (with Df(2L)Exel9043)

(Mengoli et al., 2014)

polytene chromosome | larval stage | male (with Top2^suo3)

(Mengoli et al., 2014)

primary spermatocyte (with Df(2L)Exel9043)

(Mengoli et al., 2014)

primary spermatocyte | male (with Top2^suo3)

(Mengoli et al., 2014)

secondary spermatocyte | male (with Top2^suo3)

(Mengoli et al., 2014)

spindle

(Bucciarelli et al., 2003)

Detailed Description

Statement

Reference

Top2^suo1 heterozygotes show a mild small eye phenotype.

(Yang et al., 2021)

Top2^suo1/Df(2L)Exel9043 and Top2^suo1/Top2^suo2 flies are partially lethal with a few escapers.

Top2^suo1/Df(2L)Exel9043 males display defects in chromatin organization, chromosome morphology and segregation in primary spermatocytes that include chromatin bridges and lagging chromosomal fragments, the bridges are likely to involve sister rather than non-sister chromatids.

The chromosome morphology in Top2^suo1/Top2^suo1, Top2^suo1/Df(2L)Exel9043 as well as Top2^suo1/Top2^suo3 brains is essentially normal.

The brains of Top2^suo1/Top2^suo1 and Top2^suo1/Df(2L)Exel9043 as well as Top2^suo3/Top2^suo1 transheterozygote third instar larvae (treated with colchicine and hypotonic solution) progress almost normally through mitosis although they show a significant increase in the frequency of chromosomal aberrations (including chromatin bridges and lagging chromosomal fragments) compared to wild-type. In Top2^suo1/Df(2L)Exel9043 males these aberrations are mostly isochromatid breaks preferentially involving the entirely heterochromatic Y chromosome and the third chromosome heterochromatin. In majority of metaphases with a broken Y chromosome the acentric fragment is either missing or present as an additional element. In XX females most of the aberrations are isochromatid breaks in 3L heterochromatin. The chromatin bridges are likely to involve sister rather than non-sister chromatids.

Top2^suo1/Df(2L)Exel9043 males display defects in the morphology of the polytene chromosome X in larval salivary glands. The X chromosome appears bloated and is often detached from the chromocenter. Females display normal polytene chromosome morphology.

Top2^suo1/Top2^suo3 males show highly defective meiotic chromosome morphology and aberrant segregation with chromatin bridges and lagging chromosomal fragments in primary spermatocytes during meiosis I, resulting in secondary spermatocytes dividing without any chromosomes or if they've received some they display severe segregation defects.

Top2^suo3/Top2^suo1 as well as Top2^suo3/Df(2L)Exel9043 males display defects in the morphology of the polytene chromosome X in larval salivary glands. The X chromosome appears bloated and is often detached from the chromocenter. Females display normal polytene chromosome morphology.

(Mengoli et al., 2014)

suo¹/Df(2L)VA17 mutants are severely defective in germline cell proliferation. suo¹ prometaphase and metaphase I figures are normal, but anaphases and telophases are characterised by the presence of chromatin bridges. As a result of these bridges, in 25% of suo¹ ana-telophase I cells, all the chromosomes segregate to one pole only, giving rise to chromosome-free secondary spermatocytes. suo¹ secondary spermatocytes devoid of chromosomes form a bipolar spindle that undergoes the same dynamic transformations seen in chromosome-containing spindles.

(Bucciarelli et al., 2003)

External Data

Linkouts

Interactions

Show genetic interaction network for Enhancers & Suppressors

Phenotypic Class

Enhanced by

Statement

Reference

Top2^suo1 has decreased size | adult stage | dominant phenotype, enhanceable by Tctp^RNAi.UAS/Scer\GAL4^ey.PU

(Yang et al., 2021)

Enhancer of

Statement

Reference

Top2^suo1/Top2[+] is an enhancer of decreased size | adult stage phenotype of Scer\GAL4^ey.PU, Tctp^RNAi.UAS

(Yang et al., 2021)

Phenotype Manifest In

Enhanced by

Statement

Reference

Top2^suo1 has eye phenotype, enhanceable by Tctp^RNAi.UAS/Scer\GAL4^ey.PU

(Yang et al., 2021)

Top2^suo1/Top2^suo3 has chromosome | third instar larval stage | male phenotype, enhanceable by mei-41^29D

(Mengoli et al., 2014)

Top2^suo1/Top2^suo3 has larval brain | third instar larval stage | male phenotype, enhanceable by tefu^atm-3/tefu^atm-3

(Mengoli et al., 2014)

Suppressed by

Statement

Reference

Top2^suo1/Top2^suo3 has embryonic/larval salivary gland | male | larval stage phenotype, suppressible by mof¹

(Mengoli et al., 2014)

Top2^suo1/Top2^suo3 has polytene chromosome | male | larval stage phenotype, suppressible by mof¹

(Mengoli et al., 2014)

Enhancer of

Statement

Reference

Top2^suo1/Top2[+] is an enhancer of eye | female phenotype of Scer\GAL4^ey.PU, Tctp^RNAi.UAS

(Yang et al., 2021)

Top2^suo1/Top2[+] is an enhancer of wing phenotype of Scer\GAL4^ey.PU, Tctp^RNAi.UAS

(Yang et al., 2021)

Top2^suo1/Top2^suo3 is an enhancer of chromosome | third instar larval stage | male phenotype of mei-41^29D

(Mengoli et al., 2014)

Top2^suo1/Top2^suo3 is an enhancer of larval brain | third instar larval stage | male phenotype of mei-41^29D

(Mengoli et al., 2014)

Top2^suo1/Top2^suo3 is an enhancer of chromosome | third instar larval stage | male phenotype of tefu^atm-3

(Mengoli et al., 2014)

Top2^suo1/Top2^suo3 is an enhancer of larval brain | third instar larval stage | male phenotype of tefu^atm-3

(Mengoli et al., 2014)

NOT Enhancer of

Statement

Reference

Top2^suo1/Top2[+] is a non-enhancer of eye | male phenotype of Scer\GAL4^ey.PU, Tctp^RNAi.UAS

(Yang et al., 2021)

Additional Comments

Genetic Interactions

Statement

Reference

The increased frequency of chromosomal aberrations in third instar larval brain cells characteristic for Top2^suo3/Top2^suo1, mei-41^29D/Y or tefu^atm-3/tefu^atm-3 single mutant males is enhanced further in mei-41^29D/Y;Top2^suo3/Top2^suo1 or Top2^suo3/Top2^suo1;tefu^atm-3/tefu^atm-3 double mutants.

The X polytene chromosome condensation defects observed in larval salivary glands of Top2^suo3/Top2^suo1 males can be rescued by combination with mof¹ in hemizygote state: the X polytene chromosome of mof¹/Y;Top2^suo3/Top2^suo1 double mutants shows normal condensation as well as banding pattern.

(Mengoli et al., 2014)

Xenogenetic Interactions

Statement

Reference

Complementation and Rescue Data

Comments

Images (0)

Mutant

Wild-type

Stocks (0)

Notes on Origin

Discoverer

Isolated in a cytological screen of a collection of male sterile mutants.

(Bucciarelli et al., 2003)

External Crossreferences and Linkouts ( 0 )

Synonyms and Secondary IDs (3)

Reported As

Symbol Synonym

Top2^Suo1

(Yang et al., 2021)

Top2^suo1

(Mengoli et al., 2014)

suo¹

(Mengoli et al., 2014)

Name Synonyms

Secondary FlyBase IDs

References (3)

Report Sections

Open Close