Allele Dmel\cnn^HK21

General Information
Symbol	Dmel\cnn^HK21	Species	D. melanogaster
Name		FlyBase ID	FBal0012091
Feature type	allele	Associated gene	Dmel\cnn

Map ( GBrowse )
Allele class
Mutagen	ethyl methanesulfonate
Recent Updates
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FB2013_03
FB2013_02
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Nature of the Allele
Allele class
Mutagen	ethyl methanesulfonate (Schupbach and Wieschaus, 1989)
Mutations Mapped to the Genome

Type Location Additional Notes References point mutation 2R:9,332,557..9,332,557 reported_na_change=C316T reported_pr_change=Q106@ evidence=experimental na_change=C9332557T pr_change=Q48\|cnn-PD,Q48\|cnn-PC,Q78\|cnn-PB,Q106\|cnn- PA,Q78@\|cnn-PE (Vaizel-Ohayon and Schejter, 1999)
Associated Sequence Data
DDBJ / EMBL / GenBank	DNA sequence Protein sequence Name

UniProtKB/Swiss-Prot
UniProtKB/TrEMBL

Progenitor genotype
Nature of the lesion	Statement Reference Nucleotide substitution: C316T. Amino acid replacement: Q106@. The predicted truncated protein produced lacks all three leucine zipper motifs. (Megraw et al., 1999) Amino acid replacement: Q106@. Nucleotide substitution: CAG codon is replaced by a UAG codon. Contains an stop codon within the amino terminal of the coding region. (Vaizel-Ohayon and Schejter, 1999)
Cytology
Phenotypic Data
Phenotypic Class
	cell cycle defective (Lucas and Raff, 2007, Buffin et al., 2007) female sterile (Vaizel-Ohayon and Schejter, 1999) female sterile \| recessive (Schupbach and Wieschaus, 1989, Megraw et al., 1999) lethal \| embryonic stage (Eisman et al., 2009) lethal \| embryonic stage \| maternal effect (with cnn^25cn1) (Zhang and Megraw, 2007) lethal \| embryonic stage \| maternal effect \| recessive (Schupbach and Wieschaus, 1989, Megraw et al., 1999) male sterile (Vaizel-Ohayon and Schejter, 1999) male sterile \| recessive (Megraw et al., 1999) mitotic cell cycle defective (Buffin et al., 2007) viable (Megraw et al., 1999, Vaizel-Ohayon and Schejter, 1999)
Phenotype Manifest In
	centriole (Blachon et al., 2009) centrosome (Megraw et al., 2001) centrosome & male germline stem cell (Yamashita et al., 2007) centrosome \| embryonic stage 4 (Vaizel-Ohayon and Schejter, 1999) cyst progenitor cell (with cnn^mfs3) (Cheng et al., 2011) embryo (Vaizel-Ohayon and Schejter, 1999) embryo \| maternal effect (Megraw et al., 1999) embryonic cortex & actin filament (Vaizel-Ohayon and Schejter, 1999) ganglion mother cell \| somatic clone (Cabernard and Doe, 2009) male germline stem cell & centrosome (Yamashita et al., 2003) male germline stem cell & spindle (Yamashita et al., 2003) male germline stem cell \| supernumerary (Yamashita et al., 2003) male germline stem cell \| supernumerary (with cnn^mfs3) (Yamashita et al., 2003) mitotic cell cycle (Megraw et al., 2001) neuroblast (Megraw et al., 2001) neuroblast \| somatic clone \| supernumerary (Cabernard and Doe, 2009) neuroblast \| supernumerary (Cabernard and Doe, 2009) pericentriolar material \| embryonic stage 4 (Vaizel-Ohayon and Schejter, 1999) pole cell (Lerit and Gavis, 2011) pole cell \| maternal effect (Schupbach and Wieschaus, 1989) spermatid (Blachon et al., 2009) spindle (Megraw et al., 2001, Cabernard and Doe, 2009) spindle (with cnn^mfs3) (Cheng et al., 2011) spindle \| embryonic stage (Kao and Megraw, 2009) spindle \| embryonic stage 4 (Vaizel-Ohayon and Schejter, 1999) wing (Megraw et al., 2001)
Detailed Description
	Statement Reference During the early larval stage, cnn[HK21] mutants show no defects in photoreceptor differentiation or pattern formation. However, from the mid-pupal (50%) developmental stage, the cnn[HK21] mutation causes acetylated microtubule bundle mispositioning and apical domain localisation defects. (Chen et al., 2011) Only 37% of testis somatic cyst stem cells show repositioning of the mitotic spindle during anaphase in cnn[mfs3]/cnn[HK21] males compared to 78% of cases in heterozygous controls. (Cheng et al., 2011) Mutant embryos have a reduced number of pole cells compared to controls and the pole cells that do form often have greatly reduced germ plasm. (Lerit and Gavis, 2011) In mutant spermatids, the proximal centriole-like structure forms, though the gamma-tubulin collars of the centrioles are largely reduced and almost absent or show an abnormal localization. (Blachon et al., 2009) cnn[HK21] mutants have an increased number of brain neuroblasts, and 12-13% of the metaphase neuroblasts show aberrant spindle orientation orthogonal to the apical/basal cortical polarity axis. This subset of neuroblasts showing aberrant spindle orientation always generate equal-sized siblings that both assume neuroblast identity. Single cnn[HK21] neuroblast clones often give rise to two or more neuroblast sibling cells, but never two basal ganglion mother cells. (Cabernard and Doe, 2009) Embryogenesis fails during the first few cleavage divisions in mutant animals, and most embryos examined show no signs of development. (Eisman et al., 2009) cnn[HK21] embryos exhibit a 'linked spindles' phenotype, indicative of defective cleavage furrows. (Kao and Megraw, 2009) Third-instar larval neuroblasts from cnn[HK21] mutants exhibit mitotic spindles with broad poles, lacking astral microtubules. (Wainman et al., 2009) Anaphase onset is considerably delayed in cnn[HK21] mutants. cnn[HK21] mutants normally suffer little aneuploidy (~1%) and survive to adulthood. (Buffin et al., 2007) In embryos laid by cnn[HK21] homozygous females, the centrioles are associated with appreciable amounts of PCM, but are often not properly centered within it. The centrioles appear to be constantly nucleating PCM but seem unable to maintain their connection to it. The centrioles often exhibit irregular, stochastic movements, leaving a trail of PCM behind them as they move away. As a result of this behavior, the centrioles in cnn[HK21] embryos often lose their attachment to the nuclear envelope in interphase and to the spindle poles in mitosis. The centrosomes in cnn[HK21] embryos organise astral microtubule arrays but seem unable to maintain their connection with them. when the embryos enter mitosis, many nuclei are not associated with centrioles, and anastral spindles assemble around the mitotic chromatin. Many nuclei, however, are close enough to a centriole for the astral microtubules to contribute to spindle assembly. However, these centrioles fail to maintain their position at the spindle pole and either wander around within the spindle or lose their connection to the spindle altogether. The dramatic mitotic defects in cnn[HK21] mutant embryos results from the failure of the centrioles to maintain a stable connection to the PCM and microtubules that they organise. In most cnn[HK21] neuroblasts, no prominent MTOC is detectable before nuclear envelope breakdown, and spindle assembly occurs largely by an acentrosomal pathway. Nonetheless, approximately 95 of cnn[HK21] neuroblasts ultimately divide asymmetrically, whereas approximately 4% divide symmetrically and 1% fail in cytokinesis. Although this failure rate is modest, it is still significantly higher than in wild-type. (Lucas and Raff, 2007) For homozygous mutant male germline stem cells where one of the two centrosomes is positioned next to the hub, it is essentially random whether the mother or daughter centrosome stays next to the hub (in contrast to wild type where the daughter centrosome migrates away from the hub). (Yamashita et al., 2007) In mutant males, mitotic spindles are not oriented towards the hub in about 30% of dividing germline stem cells (GSCs) examined (in contrast to wild-type males where the mitotic spindles of the GSCs are always oriented perpendicular to the hub-GSC interface). In an additional 10-20% of mutant GSCs, the spindles are properly oriented, but the proximal spindle pole is no longer closely associated with the cell cortex at the hub-GSC interface and the entire spindle is displaced away from the hub. The frequency of spindle orientation defects is highest in metaphase. Interphase centrosome positioning is partially randomised in the mutant GSCs; in more than 35% of mutant GSCs with duplicated centrosomes, neither centrosome is positioned next to the hub (in wild-type male GSCs with duplicated centrosomes, one centrosome remains adjacent to the hub). Dividing GSCs with misoriented or detached spindles, which lose attachment to the hub are seen. Hub size is not significantly different in mutant males compared to wild type. The number of germ cells associated with the hub is increased 20-30% in homozygous males, from an average of 8.94 GSCs per hub in wild type to 11.89 GSCs per hub in homozygotes. In mutant testes with many stem cells, GSCs appear crowded around the hub and often seem attached to the hub by only a small region of cell cortex. The number of germ cells associated with the hub is increased 20-30% in homozygous males, from an average of 8.94 GSCs per hub in wild type to 10.69 GSCs per hub in cnn^HK21/cnn^mfs3 males. In some cases in cnn^HK21/cnn^mfs3 testes, a GSC divides and the two daughter cells remain in contact with the hub (this is not observed in the wild type). (Yamashita et al., 2003) Adult lies have black dots on their wings. Mitotic figures from mutant larval brains have no (cnn staining) centrosomes at the spindle poles. Mutant spindles appear meiotic in character, with the smaller forth chromosomes migrating to the spindle poles precociously. Despite the absence of mitotic centrosome centrioles with normal morphology can be found. The spindle microtubules appear to assemble outward from the chromosomes. Astral microtubules are absent at prophase. cnn^HK21 neuroblasts are found to be oriented improperly approximately 22% of the time. (Megraw et al., 2001) Homozygous females produce embryos that arrest prior to cellularisation. Embryos derived from cnn^HK21/Df(2R)cnn females have severe defects in nuclear division and distribution. The embryos never achieve cellularisation. (Megraw et al., 1999) cnn^HK21 embryos show a lack of spindle pole localisation of centrosome associated antigens Cp190 and γTub23C in a variable manner, suggesting that the Microtubule Organising Centres are at least structurally and functionally impaired, or possibly missing altogether. Embryos from cnn^E2/cnn^HK21 mothers exhibit an abnormal and disorganised spatial arrangement of nuclei during syncitial divisions, becoming increasingly severe during later divisions. This leads to a cessation of development before formation of a cellular blastoderm. In contrast to wild-type, embryos from cnn^HK21 mothers show an unstructured cortical microfilament organisation during syncitial development. Syncitial embryos from cnn^E2/cnn^HK21 mothers, show abnormally shaped mitotic spindles that are characteristically squat with ill-defined poles. During interphase and prophase, a variable number (as opposed to strictly two in wild type) of spread out and less discrete astral microtubule-like structures are seen, despite having no γTub23C localising nucleating core. (Vaizel-Ohayon and Schejter, 1999) Eggs derived from homozygous females initiate development and cytoplasmic clearing occurs in a narrow zone around the egg periphery (in wild-type embryos this process is coupled to the arrival of the nuclei at the periphery). The eggs do not seem to develop beyond this stage; pole cells are not formed and cellularisation does not occur. However, about two hours after cytoplasmic clearing, the egg periphery starts to show local contractions, in what might be an attempt at gastrulation. These contractions eventually lead to eggs which typically have one or two condensed yolk balls surrounded by more transparent cytoplasm. (Schupbach and Wieschaus, 1989) maternal-effect lethal Homozygous females lay eggs in which a narrow halo of clear cytoplasm appears around the time when nuclei would be expected to migrate to the egg periphery, but no cellularization takes place. female-sterile
External Data
Linkouts
Interactions
	Show the genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by
Statement Reference cnn^HK21 has mitotic cell cycle defective phenotype, enhanceable by cnn^HK21 (Rahmani et al., 2009, Rahmani et al., 2009) cnn^HK21 has mitotic cell cycle defective phenotype, enhanceable by msd1^ex51 (Wainman et al., 2009)
Enhancer of
Statement Reference cnn[+]/cnn^HK21 is an enhancer of partially lethal - majority die \| maternal effect phenotype of Df(2L)Fs(2)Ket-RX32/Cen^f04787 (Kao and Megraw, 2009) cnn^HK21 is an enhancer of mitotic cell cycle defective phenotype of cnn^HK21 (Rahmani et al., 2009, Rahmani et al., 2009) cnn^HK21 is an enhancer of mitotic cell cycle defective phenotype of mad2^G6595/mad2^G6595 (Rahmani et al., 2009) cnn^HK21 is an enhancer of mitotic cell cycle defective phenotype of msd1^ex51 (Wainman et al., 2009)
Other
Statement Reference BubR1^{KEN.T:Disc\RFP-mRFP}, cnn^HK21 has lethal \| pupal stage phenotype (Rahmani et al., 2009) BubR1^{KEN.T:Disc\RFP-mRFP}, cnn^HK21 has mitotic cell cycle defective phenotype (Rahmani et al., 2009) cnn^HK21, mad2^G6595/mad2^G6595 has cell cycle defective phenotype (Buffin et al., 2007) cnn^HK21, mad2^G6595/mad2^G6595 has lethal phenotype (Buffin et al., 2007) cnn^HK21, mad2^G6595/mad2^G6595 has mitotic cell cycle defective phenotype (Buffin et al., 2007) cnn^HK21, msd1^ex51 has lethal phenotype (Wainman et al., 2009)
Phenotype Manifest In
Enhancer of
Statement Reference cnn[+]/cnn^HK21 is an enhancer of eye phenotype of Scer\GAL4^GMR.PF, baz^Scer\UAS.cKa (Chen et al., 2011)
Additional Comments
Genetic Interactions
Statement Reference A cnn[HK21] heterozygous background dominantly enhances the rough eye phenotype found upon expression of baz[Scer\UAS.cKa] by Scer\GAL4[GMR.PF]. (Chen et al., 2011) Presence of a single copy of cnn[HK21] enhances the rate of embryo hatch failure from Cen[f04787]/Df(2L)Fs(2)Ket-RX32 mothers. (Kao and Megraw, 2009) mad2[G6595] cnn[HK21] double mutants exhibit a shortened prometaphase with an increase in aneuploidy compared to both single mutants and are larval lethal. BubR1[A1204K.PR] cnn[HK21] double mutants exhibit low aneuploid rates as in the single mutants and survive to adulthood. Double mutants of BubR1[KEN.T:Disc\RFP-mRFP] and cnn[HK21] are pupal lethal with aneuploidy averaging 15%. (Rahmani et al., 2009) cnn[HK21];msd1[ex51] double mutants are homozygous lethal, dying at an early pupal stage. cnn[HK21];msd1[ex51] mutants show "metaphase-like" cells with weak, unorganized microtubule arrays; very few robust spindles are observed. An increased mitotic index is observed in these double mutants, greater than the increase seen in either cnn[HK21] or msd1[ex51] single mutants, and a dramatic increase in metaphase-to-anaphase ratio. Microtubule nucleation around chromatin in cnn[HK21];msd1[ex51] mutants is still observed, similar to that seen during prometaphase in cnn[HK21] mutants, suggesting that nucleation of microtubules from around mitotic chromatin is insufficient for viability. (Wainman et al., 2009) mad2[G6595] cnn[HK21] double mutants exhibit a severely delayed sindle assembly pathway, resulting in a higher mitotic index and a broad peak anaphase onset time of 8-16 minutes. Larval brains of mad2[G6595] cnn[HK21] double mutants have a very high incidence of polyploidy and mad2[G6595] cnn[HK21] individuals die as early pupae. (Buffin et al., 2007)
Xenogenetic Interactions
Statement Reference
Complementation & Rescue Data
Fails to complement	cnn^mfs1 (Megraw et al., 1999) cnn^mfs2 (Megraw et al., 1999) cnn^mfs3 (Megraw et al., 1999) cnn^mfs7 (Megraw et al., 1999) cnn^mfs8 (Megraw et al., 1999)
Rescued by	cnn^HK21/cnn^25cn1 is rescued by Scer\GAL4^{nos.UTR.T:Hsim\VP16}/cnn^{WT.Scer\UAS.T:Avic\GFP-EGFP} (Zhang and Megraw, 2007) cnn^HK21 is rescued by cnn^+mVa (Vaizel-Ohayon and Schejter, 1999) cnn^HK21 is rescued by cnn^otu.PV (Vaizel-Ohayon and Schejter, 1999)
Not rescued by	cnn^HK21/cnn^25cn1 is not rescued by cnn^{Δ1.Scer\UAS.T:Avic\GFP-EGFP}/Scer\GAL4^{nos.UTR.T:Hsim\VP16} (Zhang and Megraw, 2007) cnn^HK21 is not rescued by Scer\GAL4^{nos.UTR.T:Hsim\VP16}/cnn^{PA.Scer\UAS.P\T.T:Avic\GFP} (Eisman et al., 2009)
Comments	Expression of cnn[PA.Scer\UAS.P\T.T:Avic\GFP] under the control of Scer\GAL4[nos.UTR.T:Hsim\VP16] does not rescue the cnn[HK21] mutant phenotype; none of the eggs produced by cnn[HK21] females expressing cnn[PA.Scer\UAS.P\T.T:Avic\GFP] under the control of Scer\GAL4[nos.UTR.T:Hsim\VP16] hatch. (Eisman et al., 2009)
Stocks ( 2 )
Bloomington	5039 cn¹ cnn^HK21 bw¹/CyO, l(2)DTS513¹
Kyoto	108003 cn¹ cnn^HK21 bw¹/CyO, l(2)DTS513¹
Notes on Origin
Discoverer

Comments
	Complements alleles of arr for viability and fertility. (Vaizel-Ohayon and Schejter, 1999)
External Crossreferences & Linkouts
Other Crossreferences

Linkouts

Synonyms & Secondary IDs ( 9 )
Reported As
Symbol Synonym	cnn^HK2 (Cabernard and Doe, 2009) cnn^hk21 (Megraw et al., 2002, Megraw et al., 2001, Wainman et al., 2009, Chen et al., 2011, Eisman et al., 2009, Buffin et al., 2007, Zhang and Megraw, 2007, Kao and Megraw, 2009) cnn^HK21 (Christensen and Cook, 2007.3.22, Christensen and Cook, 2007.3.22, Christensen and Cook, 2007.5.8, Yamashita et al., 2007, Yamashita et al., 2007, Lee et al., 2006, Slack et al., 2007, Blachon et al., 2009, Cabernard and Doe, 2009, Lucas and Raff, 2007, Rahmani et al., 2009, Cheng et al., 2011, Lerit and Gavis, 2011) cnn^HK (Vaizel-Ohayon and Schejter, 1999) hk21 (Megraw et al., 1999) hk21^null (Eisman et al., 2009) mat(2)syn^HK21 (Vaizel-Ohayon and Schejter, 1999) mat(2)syn-C¹ mat(2)synHK21 (Schupbach and Wieschaus, 1989, )
Name Synonym
Secondary FlyBase IDs

References ( 27 )

Generate a list of	All references relating to this allele ( 27 )

List References by type	Research paper ( 23 ) Supplementary material ( 1 ) Personal communication to FlyBase ( 3 )
Recent research papers ( 3 )
	Chen et al., 2011, PLoS ONE 6(1): e16127 Genetic interaction of centrosomin and bazooka in apical domain regulation in Drosophila photoreceptor. [FBrf0212822] Cheng et al., 2011, Development 138(5): 831--837 Asymmetric division of cyst stem cells in Drosophila testis is ensured by anaphase spindle repositioning. [FBrf0213009] Lerit and Gavis, 2011, Curr. Biol. 21(6): 439--448 Transport of germ plasm on astral microtubules directs germ cell development in Drosophila. [FBrf0213255] Show all research papers ...

Allele Dmel\cnnHK21

Allele Dmel\cnn^HK21