FlyBase Allele Report: Dmel\Sgt1[c01268]

General Information

Symbol

Dmel\Sgt1^c01268

Species

D. melanogaster

Name

FlyBase ID

FBal0184573

Feature type

allele

Associated gene

Dmel\Sgt1

Associated Insertion(s)

PBac{PB}Sgt1^c01268

Carried in Construct

Key Links

Genomic Maps

JBrowse

Allele class

Mutagen

piggyBac activity

Nature of the Allele

Allele class

Mutagen

piggyBac activity

(Gene Disruption Project members and Exelixis, 2005)

Progenitor genotype

Associated Insertion(s)

PBac{PB}Sgt1^c01268

Cytology

Description

Insertion at nucleotide +55 of the transcription unit, which is upstream of the initiator ATG codon.

(Martins et al., 2009)

Allele components

Component

Use(s)

Also carries

FRT

recombinase target site

Mutations Mapped to the Genome

Curation Data

Type

Location

Additional Notes

References

transposable_element_insertion_site

3R:8,305,203..8,305,203 [-]

(Martins et al., 2009, Gene Disruption Project members and Exelixis, 2005)

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

abnormal mitotic cell cycle | third instar larval stage

(Martins et al., 2009)

lethal (with Df(3R)CA3)

(Martins et al., 2009)

lethal | recessive

(Martins et al., 2009)

Phenotype Manifest In

centriole

(Martins et al., 2009)

centrosome

(Martins et al., 2009)

neuroblast

(Martins et al., 2009)

spindle

(Martins et al., 2009)

Detailed Description

Statement

Reference

Third larval instar Sgt1^c01268 neuroblasts have abnormal mitotic phenotypes, including a high proportion of prometaphases with hypercondensed chromosomes and anaphases with lagging chromatids. Sgt1^c01268 has no overall effect upon mitotic index. There is a significant reduction in the frequency of prophases, a severe increase in the frequency of prometaphases and a reduction of cells exiting mitosis compared to control cells. Compared to controls, many fewer mutant neuroblasts incorporate BrdU.

Treatment of Sgt1^c01268 neuroblasts with colchicine does not lead to the accumulation of cells in mitosis, in contrast to control cells.

22% of Sgt1^c01268 neuroblasts have monopolar spindles, with either a dispersed or well-focused centrosome at the centre. 30% of cells have just one centrosome and 20% have a diffuse centrosome.

When Sgt1^c01268 larval neuroblasts are observed in primary culture, the following mitotic behaviours are observed; 55% enter mitosis with no apparent microtubule-organizing centre (MTOC), but after nuclear envelope breakdown (NEBD) are able to form a microtubule array that grows out from the kinetochores, they are unable to focus at the spindle poles and mitotic progression is delayed in prometaphase for more than 1 hours. 15% of the cells enter mitosis with a single MTOC, form a bipolar spindle and reach metaphase with a short delay but eventually exit mitosis with a significant delay (35 minutes after NEBD). 5% of the cells enter mitosis with more than two MTOCs, fail to organise a proper bipolar spindle and consequently fail to congress the chromosomes and arrest for long periods. 25% of the mutant neuroblasts enter mitosis with two MTOCs (as occurs in wild type).

Only 40% of Sgt1^c01268 neuroblasts have a normal set of centriole pairs, approximately 40% have more than two centriole pairs and some cells have less than two centriole pairs. There is a clear correlation between increase in centriole number and increase in ploidy in the mutant cells.

(Martins et al., 2009)

External Data

Linkouts

Interactions

Show genetic interaction network for Enhancers & Suppressors

Phenotypic Class

Suppressed by

Statement

Reference

Sgt1^c01268 has abnormal mitotic cell cycle | third instar larval stage phenotype, suppressible | partially by polo^UASp.cMa/Scer\GAL4^da.G32

(Martins et al., 2009)

Other

Statement

Reference

Bub3¹, Sgt1^c01268 has abnormal mitotic cell cycle phenotype

(Martins et al., 2009)

Phenotype Manifest In

Suppressed by

Statement

Reference

Sgt1^c01268 has centrosome phenotype, suppressible | partially by polo^UASp.cMa/Scer\GAL4^da.G32

(Martins et al., 2009)

Sgt1^c01268 has spindle phenotype, suppressible | partially by polo^UASp.cMa/Scer\GAL4^da.G32

(Martins et al., 2009)

Sgt1^c01268 has neuroblast phenotype, suppressible | partially by polo^UASp.cMa/Scer\GAL4^da.G32

(Martins et al., 2009)

Additional Comments

Genetic Interactions

Statement

Reference

Sgt1^c01268 ; Bub3¹ double mutant larval brain neuroblasts have a very low mitotic index. Compared to Sgt1^c01268 single mutant cells, the Sgt1^c01268 ; Bub3¹ double mutant cells enter mitosis more readily, do not accumulate in prometaphase and exit mitosis more frequently (as shown by the increase in anaphase and telophase figures). The double mutant cells do not show chromosome hypercondensation.

Expression of polo^{Scer\UAS.P\T.cMa} under the control of Scer\GAL4^da.G32 significantly rescues the mutant phenotypes of Sgt1^c01268 larval brain neuroblasts; there is an increase in cells with a normal number of centrosomes and a normal bipolar spindle and the cells show mostly normal mitotic progression.

(Martins et al., 2009)

Xenogenetic Interactions

Statement

Reference

Complementation and Rescue Data

Comments

Images (0)

Mutant

Wild-type

Stocks (1)

Bloomington

85947

w¹¹¹⁸; PBac{PB}Sgt1^c01268

Notes on Origin

Discoverer

Comments

Precise excision of the insertion results in a full restoration of viability.

(Martins et al., 2009)

External Crossreferences and Linkouts ( 0 )

Synonyms and Secondary IDs (3)

Reported As

Symbol Synonym

CG9617^c01268

Sgt1^c01268

sgt1^P1

(Martins et al., 2009)

Name Synonyms

Secondary FlyBase IDs

References (2)

Report Sections

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