Open Close
General Information
D. melanogaster
FlyBase ID
Feature type
Associated gene
Associated Insertion(s)
Carried in Construct
Key Links
Nature of the Allele
Mutations Mapped to the Genome
Additional Notes
Nucleotide change:


Amino acid change:

V242E | polo-PA; V242E | polo-PB

Reported amino acid change:



Site of nucleotide substitution in mutant inferred by FlyBase based on reported amino acid change.

Associated Sequence Data
DNA sequence
Protein sequence
Progenitor genotype
Nature of the lesion

Amino acid replacement: V242E.

Point mutation or small deletion in the coding region.

Expression Data
Reporter Expression
Additional Information
Marker for
Reflects expression of
Reporter construct used in assay
Human Disease Associations
Disease Ontology (DO) Annotations
Models Based on Experimental Evidence ( 0 )
Modifiers Based on Experimental Evidence ( 1 )
Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
Disease-implicated variant(s)
Phenotypic Data
Phenotypic Class
Phenotype Manifest In

meiosis II & aster | female

meiosis II & spindle | female

meiotic cell cycle & spindle | male

meiotic metaphase II & spindle | female

meiotic telophase II & contractile ring | female

neuroblast & centrosome & larva

neuroblast & mitotic anaphase & larva

spermatocyte & midbody

spermatocyte & pericentriolar material

spermatocyte & spindle

Detailed Description

polo1/+ does not significantly affect number of boutons or branches at the larval neuromuscular junction, locomotion (larval or adult), or lifespan.

Approximately 90% of polo1/poloS025604 germaria have a 'two-oocyte phenotype' in region 3 (a single oocyte is already determined in approximately 70% of wild-type germaria by this stage).

In polo1 neuroblasts, the aster is lost soon after mitosis and none of the two centrosomes remain cortex bound in interphase.

polo1 homozygotes are viable, though females are completely sterile.

Meiosis does not initiate properly in region 2a of the polo1/poloS025604 germarium. Cysts often contain abnormal synaptonemal complexes and meiosis restriction to one cell is delayed.

The non-disjunction phenotype seen in mei-S3328/+ sperm is partially suppressed by polo1.

polo1/polo16-1 females do not show gross defects in meiotic spindle formation.

Mutant larval brains have a mitotic index that is elevated about 4-fold above that of wild-type cells. The metaphase/anaphase ratio is 11.6 compared to 5.8 in wild-type cells. 2.3% of mitotic cells are aneuploid or polyploid. A small fraction (0.7%) of circular mitotic figures is seen.

No appreciable differences are seen between the organisation of the first meiotic spindle in oocytes produced by homozygous females and wild-type oocytes.In contrast, eggs derived from homozygous females show a number of abnormal features that appear to be linked to a delay in progression through the second meiosis. The metaphase II spindles appear abnormal; firstly, the meiotic figures are not aligned particularly well perpendicular to the egg surface, and secondly, although the microtubule array of the central spindle pole body is well developed, the microtubules do not appear to have a well organised focus. It appears that as metaphase progresses in these eggs, the twin spindles move away from each other and the central aster expands as a disorganised array of microtubules. This pattern of spindle organisation appears to persist through early anaphase.

The central aster is reduced in size to become barely detectable from late anaphase onwards. At this time, the meiotic spindles appear elongated and narrowed in their midzone. During telophase the spindle is no longer visible and the two minispindles appear connected by a thin bridge of microtubules. These spindle microtubules appear to have regressed by the end of telophase such that the haploid complements of chromosomes are misaligned. Midbody microtubules have been detected in only 2 out of 38 telophase figures examined. The sperm aster in eggs derived from homozygous females is comparable in size and organisation to that seen in wild type towards the end of meiosis I and the onset of meiosis II. Astral microtubules are short and focused toward several points. By the end of metaphase II the sperm aster is often seen to have divided to give two smaller astral arrays of microtubules which are more widely separated from the male pronucleus than in wild-type. The sperm aster increases in dimensions from telophase onwards, but the microtubules never extend to the egg cortex (as in wild type) and do not interact with the putative female pronucleus. The sperm aster defects cannot be rescued by a paternal copy of polo[+]. 88% of eggs derived from wild-type females can be fertilised by homozygous males, and all show a wild-type meiotic phenotype.

Female meiosis and the sperm centrosome cycle are uncoupled in eggs derived from homozygous females. Close juxtaposition or contact of the male and female pronuclei after the completion of meiosis is only seen in 2.1% of eggs derived from homozygous females. The gonomeric spindle is never formed, and instead a bipolar spindle is established around the haploid paternal complement. In 87% of cases only one centrosome is found in association with a single pole at this spindle, whereas the other centrosome remains free at a slight distance. Pronuclear fusion does not occur in eggs derived from homozygous females, and all four haploid complements derived from the female meiosis retreat to a position immediately below the embryo surface. All four haploid components continue to undergo division cycles (in contrast to wild type where they stop cycling during the first metaphase). The chromosomes become associated with anastral bipolar spindles strongly resembling meiotic spindles. The nuclei associated with these anastral spindles undergo several divisions and populate the embryo surface, while the spindle organised around the male complement is generally unable to divide, although its centrosomes replicate. Only those male derived nuclei associated with spindles retaining both centrosomes are able to divide several times, in which case embryos are seen in which anastral and biastral spindles populate the same cytoplasm. The biastral spindles behave abnormally and give rise to occasional syncytial blastoderm embryos with scattered centrosomes and irregularly sized nuclei. Although sister chromatids successfully segregate during anaphase of these haploid divisions, spindles with abnormal chromosome content are frequently seen.

Eggs derived from virgin homozygous females under meiosis (as in wild type) but do not form polar bodies. About 60% of eggs observed 30 minutes after oviposition contain many anastral bipolar spindles, that are similar to spindles observed in fertilised eggs derived from homozygous females.

Eggs derived from polo1/poloDD1 females complete meiosis and show a phenotype similar to that of eggs derived from polo1 females; they contain many bipolar anastral spindles but lack structures containing polar bodies.

56.7% of fertilised eggs derived from polo1/poloDD6 females have two major bipolar anastral spindles 30 minutes after oviposition, indicating arrest in meiosis. 15.3% have 3 spindles and 11.3% have 4 spindles, suggesting some progression through anaphase/telophase of the second meiosis. In these cases, chromosomes are found at the equator of spindles or scattered within them. No more than 5 anastral spindles are seen in these embryos. The sperm aster splits in two during late metaphase II, but its centrosome is unable to drive the formation of a biastral spindle, so that the male haploid complement is associated with a bipolar anastral spindle.

Giant gonial cells containing multiple microtubule-organising centres (MTOCs) are seen in the testes of homozygous males. Primary spermatocyte cysts may contain enlarged cells and the number of ring canals is reduced. Many late anaphase-telophase spermatocytes show defects in the appearance of the central region of the spindle. Many bipolar spindles fail to constrict at telophase, failing to form the mid-body seen in wild-type cysts. Cells which have not formed the mid-body lack the actin ring. Tetrapolar cells containing 4 MTOCs in which cytokinesis has failed in both meiotic divisions are seen. 69% of meiotic cells in homozygous testes show normal meiosis. Meiotic abnormalities are very rare at metaphase of the first division, but defects from anaphase I onwards are found in 31% of cells. There is a loss of synchrony of meiotic divisions compared to wild-type. 82.8% of onion stage spermatids appear normal. Others have varying numbers of nuclei, with binucleate (13.1%) and tetranucleate cells (2.7%) being the most frequent. These abnormal cells have a single enlarged Nebenkern, and indicate a failure of cytokinesis in either one or both meiotic divisions. Spermatids with two or four axonemes are frequently seen. polo1/poloDD6 and polo1/poloDD1 males show defects in spermatogenesis.

The frequency of mitotic figures in the polo1 larval brain is higher than in wild-type. 20.1% of mitotic figures are polyploid and 15.5% are circular.

Approximately 20% of homozygotes survive to adulthood. The testes of homozygous, hemizygous and polo1/polo2 males show cytological abnormalities during all stages of spermatogenesis. Primary spermatocytes containing less than the wild-type number of 16 cells (usually containing 14 cells of normal size and 1 large cell) are seen. The overall organisation of the spindles of metaphase I cysts is defective. Metaphase II cysts have severe abnormalities. Cysts in the second meiotic division are mostly incomplete and highly disorganised. Onion stage cysts contain a variable number of cells, with variable nuclear and Nebenkern volume. The overall organisation of the spindles of metaphase I cysts in the testes of polo1/polo2 males is defective; the spindles appear shorter and thicker than wild-type, showing large asters of microtubule bundles.

rlSu14 and Dsor1Su1 have no effect on the mutant phenotype.

Homozygous larval neuroblasts have smaller centrosomes than normal. The cells often contain one broad/disorganised centrosome while the other is smaller. Abnormal anaphases are seen where the chromatids have migrated normally to the organised pole but are completely misaligned on the other half spindle.

Semilethal, 7% homozygotes survive as adults. Homozygous females produce embryos with severe mitotic abnormalities; multiple rounds of DNA replication with limited nuclear division, embryos do not cellularise and never hatch.

Third instar larvae often show aberrant mitosis in neuroblasts in the brain.

recessive semi-lethal; a few survivors

External Data
Show genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by

gwlscant, polo[+]/polo1 has female semi-sterile | dominant phenotype, enhanceable | maternal effect by mts[+]/mtsXE-2202

gwlscant, polo[+]/polo1 has female semi-sterile | dominant phenotype, enhanceable | maternal effect by endos+tRa/endos[+]

gwlscant, polo[+]/polo1 has female semi-sterile | dominant phenotype, enhanceable | maternal effect by twsaar-1/tws[+]

gwlscant, polo[+]/polo1 has female semi-sterile | dominant phenotype, enhanceable | maternal effect by tws[+]/twsj11C8

polo1 has lethal phenotype, enhanceable by Cdc27S092309

Suppressed by
NOT suppressed by
Enhancer of

polo1 is an enhancer of lethal phenotype of Cdc27S092309

Suppressor of
Phenotype Manifest In
Enhanced by

polo1 has aster & neuroblast phenotype, enhanceable by Cdc27S092309

polo1 has spindle & neuroblast phenotype, enhanceable by Cdc27S092309

Suppressed by
NOT suppressed by
Enhancer of

polo1 is an enhancer of aster & neuroblast phenotype of Cdc27S092309

polo1 is an enhancer of spindle & neuroblast phenotype of Cdc27S092309

Suppressor of
Additional Comments
Genetic Interactions

Expression of maelS138D.Scer\UAS.P\T.T:Zzzz\FLAG under the control of Scer\GAL4nos.PG partially suppresses the defect in oocyte commitment (high frequency of 'two-oocyte phenotype' in region 3 of the germarium) that is seen in polo1/poloS025604 germaria.

Expression of maelS138A.Scer\UAS.P\T.T:Zzzz\FLAG under the control of Scer\GAL4nos.PG does not suppress the defect in oocyte commitment (high frequency of 'two-oocyte phenotype' in region 3 of the germarium) that is seen in polo1/poloS025604 germaria.

Sir217/+ suppresses the defect in oocyte commitment (high frequency of 'two-oocyte phenotype' in region 3 of the germarium) that is seen in polo1/poloS025604 germaria.

pch2EY01788a/pch2EY01788a suppresses the defect in oocyte commitment (high frequency of 'two-oocyte phenotype' in region 3 of the germarium) that is seen in polo1/poloS025604 germaria.

polo1/+ gwlscant/+ double heterozygous females are nearly sterile. This phenotype is partially suppressed if the females are also heterozygous for either endosEY01105 or endosEY01103.

Heterozygosity for either twsaar-1, twsj11C8 or mtsXE-2202 enhances the reduced fertility phenotype of polo1/+ gwlscant/+ double heterozygous females, such that in each case the triple heterozygotes are completely sterile.

endos+tRa enhances the reduced fertility phenotype of polo1/+ gwlscant/+ double heterozygous females, such that in each case the triple heterozygotes are completely sterile.

polo1 gwlscant double heterozygous females produce 4% as many progeny as controls.

polo1 gwlscant mitotic nuclei exhibit centrosomal loss in just under approximately 60% of syncytial embryos.

polo1 gwlscant double heterozygous females produce embryos that frequently display centrosome disassociation from one pole. There is a slight but significant increase in defective spindles in embryos derived from polo1 gwlscant mutants compared to controls, indicating that a single mutant copy of these genes in mothers leads to mitotic defects at a low frequency. However, these embryos always hatch and develop fully, indicating that such low frequencies of defects can be tolerated.

The lethal phase of Cdc27S092309 is advanced to an earlier developmental stage when in combination with polo1. The stage of death is also earlier than with polo1 alone. In terms of the mitotic index, the metaphase:anaphase ratio, the condensation state of the chromosomes and the levels of mitotic cyclins, the phenotype of Cdc27S092309 polo1 cells do not differ significantly from that of the Cdc27S092309 single mutant. The polo1 phenotype with respect to centrosomal defects is enhanced by the Cdc27S092309 mutation. Mitotically arrested Cdc27S092309 polo1 cells, lack the MPM2 epitope at their spindle poles, consistent with diminished levels of polo kinase activity at the spindle poles. Cdc27S092309 is epistatic to polo1 in respect of mitotic progression and cyclin degradation. Cdc27S092309 polo1 double mutant cells display overcondensed chromosomes. In Cdc27S092309 polo1 double mutants the mitotic index, proportions of metaphase:anaphase cells and the proportion of polyploids are similar to that in the Cdc27S092309 mutant alone.

The fraction of embryos derived from lokE51 females which have abnormal nuclei is reduced (from 61.5 +/- 1.1%) if the females also carry one copy of polo1 (to 27.0 +/- 3.2% of embryos).

polo1 mgrunspecified double mutants show a phenotype more similar to mgrunspecified than polo1 single mutants, although the frequency of circular figures appears to be additive. aspE3 polo1 double mutants show mitotic abnormalities similar to those seen in aspE3 single mutants, including polyploid and aneuploid cells with various degrees of chromosome condensation. There are a large number of cells in metaphase, and unlike the polo1 single mutant, no normal metaphase or anaphase figures and no circular mitotic figures are seen. The mitotic frequency of the double mutant and the frequency of polyploid cells are dramatically increased compared to that of either single mutant, indicating a synergistic effect.

Xenogenetic Interactions

polo1/+ partially suppresses the wing expansion defects, shorter lifespan, locomotion defects (larval and adult), and increases of Is bouton numbers (but does not suppress branch number changes or the decrease of Ib boutons) at the larval neuromuscular junction seen in animals with Hsap\APP695.Scer\UAS driven by Scer\GAL4Appl.G1a.

Expression of Mmus\Plk1Scer\UAS.P\T.T:Avic\GFP under the control of Scer\GAL4mat.αTub67C.T:Hsim\VP16 does not rescue the sterility of polo1/poloS025604 females.

Complementation and Rescue Data
Partially rescued by

polowt.T:Avic\GFP substantially rescues the sterility of polo1/Df(3L)rdgC-co2 females: in the presence of one copy of polowt.T:Avic\GFP the rescued females produce an average of 23.9 progeny per female over 18 days when mated to wild-type males and in the presence of two copies, produce an average of 30.9 progeny per female.

poloH518A.K520M.T:Avic\GFP fails to rescue the sterility of polo1/Df(3L)rdgC-co2 females.

poloT:Avic\GFP rescues the sterility of polo1/poloS025604 females.

Images (0)
Stocks (2)
Notes on Origin


External Crossreferences and Linkouts ( 0 )
Synonyms and Secondary IDs (1)
References (34)