|Feature type||allele||Associated gene||Dmel\Cap-H2|
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|Nature of the Allele|
|Mutations Mapped to the Genome|
|Associated Sequence Data|
|Nature of the lesion|
A to T change in the first intron and a G to A mutation that changes a Trp residue to a stop codon.
Nucleotide substitution: A?T.
Nucleotide substitution: G?A.
Amino acid replacement: W?@.
|Phenotype Manifest In|
Polyteny persists in 100% of the nurse cells in stage 10 egg chambers of Cap-H2[Z3-0019]/Cap-H2[Z3-5163] and Cap-H2[Z3-0019]/Df(3R)Exel6159 females (in contrast to wild-type nurse cells, which disassemble their polytene chromosomes during mid-oogenesis).
Homozygous nurse cells do not exhibit an alteration in endocycling compared to controls; there is no significant difference in the number of homozygous and heterozygous nurse cells undergoing S phase per stage 5, 6, 10 and 11/12 egg chambers. Homozygous nurse cells do not show a change in DNA replication content compared to controls. Homozygous larval neuroblasts do not show a change in cell cycle regulation compared to controls (assayed using flow cytometry analysis).
Cap-H2[Z3-0019]/Df(3R)Exel6159 and Cap-H2[Z3-0019]/Cap-H2[TH1] transheterozygous males are sterile. Cap-H2[Z3-0019] homozygous males are seemingly devoid of sperm, indicating a defect in gamete production. Cap-H2[Z3-0019]/Cap-H2[Z3-5163] mutants exhibit decreased fertility. There is no significant difference in male fertility between Cap-H2[Z3-0019]/Cap-H2[Z3-5163] and Cap-H2[Z3-5163]/+ males. Sex chromosome nondisjunction is not found in Cap-H2[Z3-0019], Cap-H2[Z3-0019]/Cap-H2[Z3-5163] or Cap-H2[Z3-0019]/+ mutants. Fourth chromosome segregation does not differ substantially between Cap-H2[Z3-0019]/Cap-H2[Z3-5163] and Cap-H2[Z3-0019] heterozygous control males. Cap-H2[Z3-0019]/Cap-H2[Z3-5163] mutants exhibit an elevated level of exceptional progeny where the second or third chromosomes are exceptional. in both cases the exceptional class most over represented are those from fertilization events involving sperm that lack a 2nd or 3rd chromosome. Cap-H2[Z3-0019]/Cap-H2[Z3-5163] and Cap-H2[Z3-0019]/+ mutants exhibit meiosis I nondisjunction. There may also be a slight increase in meiosis II nondisjunction. In male sterile mutants of the genotype Cap-H2[Z3-0019]/Cap-H2[TH1], chromosomal organizational steps throughout prophase I are defective, as normal territory formation is never observed in 100% of S2, S4, and S6 stages. Instead, chromatin is seemingly dispersed within the nucleus. No prophase I defects are observed in Cap-H2[Z3-0019]/Cap-H2[Z3-5163] males, although subtle morphological changes may be difficult to detect. M1 of meiosis I may be morphologically abnormal in Cap-H2[Z3-0019]/Cap-H2[TH1] mutants. Despite not forming normal chromosome territories and possibly never reaching normal M1 chromosomal structure, there are no unusual features detected in Cap-H2[Z3-0019]/Cap-H2[TH1] male sterile metaphase I figures. Anaphase I is clearly not normal in Cap-H2[Z3-0019]/Cap-H2[TH1] mutants, where bridges are often found between segregating sets of chromosomes. The frequency of these bridges occurs in a manner tha matches other phenotypic trends, found in 30.4% of the anaphase I figures for sterile Cap-H2[Z3-0019]/Cap-H2[TH1] males, 11.5% for Cap-H2[Z3-0019]/Cap-H2[TH1] males that are fertile yet undergo 2nd and 3rd chromosome loss, and never in the wild-type. Whereas bridging anaphase I figures are never observed in wild-type squashed chromosome preparations, bridging occurs in 40.5% of those from Cap-H2[Z3-0019]/Cap-H2[TH1] mutant males. Of the total anaphase I figures from Cap-H2[Z3-0019]/Cap-H2[TH1] mutant testes, 21.4% appear to have anaphase I bridging between homologous chromosomes. The 4th chromosome is bridged in 4.8% of anaphase I figures. As an expected outcome of cosegregation in meiosis I, aneuploidy in prophase II and anaphase II figures is observed. In onion stages from Cap-H2[Z3-0019] homozygotes, micronuclei are often observed which may be the manifestation of chromatin lost through anaphase I bridging.
|Phenotype Manifest In|
Cap-H2Z3-0019/Cap-H2[+] is an enhancer of polytene chromosome & nurse cell phenotype of Cap-D3EY00456/Df(2L)Exel7023
The severity of the Ubx[1:Cbx-1]/+ wing phenotype is dominantly enhanced by Cap-H2[Z3-0019]; the proportion of flies that show blistering or necrosis of the wing is increased. The severity of the T(2;3)BTD71/+ wing phenotype is dominantly enhanced by Cap-H2[Z3-0019]; the proportion of flies that show withering at the posterior of the wing is increased.
The persistence of polyteny that is seen in the nurse cells of stage 10 egg chambers of Cap-D3[EY00456]/Df(2L)Exel7023 females is enhanced by Cap-H2[Z3-0019]/+; the penetrance of the phenotype is enhanced from 91.3 +/- 2.3% to 100%. 77.3 +/- 9.1% of the nurse cells in stage 10 egg chambers of glu[k08819]/+ ; Cap-H2[Z3-0019]/+ double heterozygous females show persistence of polyteny, with the chromosomes having a loosened, but clear, polytene morphology. Body colour: The reduced body pigmentation seen in y[1#8]/y[82f29] flies is partially suppressed by Cap-H2[Z3-0019]/Df(3R)Exel6159.
A glu[k08819] heterozygous background lead to a substantial decrease in fertility for Cap-H2[Z3-5163]/Cap-H2[Z3-0019] mutants. While 30.4% of anaphase I figures from Cap-H2[Z3-0019]/Cap-H2[TH1] males are bridged, bridging is found within only 10.8% of anaphase I figures in a heterozygous tef[Z5549]/tef[Z5864] background. In squashed preparations anaphase I bridging is decreased from 40.5% in Cap-H2[Z3-0019]/Cap-H2[TH1] males to 25.6% in a heterozygous tef[Z5549]/tef[Z5864] background. The percent of anaphase I figures where homozygous chromosomes appear to be bridged decreases from 21.4 in Cap-H2[Z3-0019]/Cap-H2[TH1] mutants to 9.3% in a heterozygous tef[Z5549]/tef[Z5864] background. Fourth chromosomes-to-heterolog threads are greatly suppressed in a heterozygous tef[Z5549]/tef[Z5864] background.
|Complementation & Rescue Data|
|Fails to complement|
|Stocks ( 0 )|
|Notes on Origin|
|External Crossreferences & Linkouts|
|Synonyms & Secondary IDs ( 2 )|
|Secondary FlyBase IDs|
|References ( 4 )|