Allele Dmel\chb⁴

General Information
Symbol	Dmel\chb⁴	Species	D. melanogaster
Name		FlyBase ID	FBal0104955
Feature type	allele	Associated gene	Dmel\chb
Also Known As	orbit⁴

Allele class	amorphic allele - genetic evidence
Mutagen	Delta2-3
Recent Updates
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FB2013_03
FB2013_02
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Nature of the Allele
Allele class	amorphic allele - genetic evidence (Inoue et al., 2000)
Mutagen	Delta2-3 (Inoue et al., 2000)
Mutations Mapped to the Genome

Type Location Additional Notes References
Associated Sequence Data
DDBJ / EMBL / GenBank	DNA sequence Protein sequence Name

UniProtKB/Swiss-Prot
UniProtKB/TrEMBL

Progenitor genotype	chb^S068607 (Inoue et al., 2000) P{lacW}chb^S068607 (Inoue et al., 2000)
Nature of the lesion	Statement Reference Imprecise excision of the P{lacW} element, resulting in a deletion extending from within the asparagine-synthetase gene to within the chb gene. (Inoue et al., 2000)
Caused by aberration	Df(3L)chb⁴ (Inoue et al., 2000)
Cytology
Phenotypic Data
Phenotypic Class
	mitotic cell cycle defective \| recessive (Inoue et al., 2000) neuroanatomy defective (Lee et al., 2004) neuroanatomy defective (with chb²) (Lee et al., 2004)
Phenotype Manifest In
	intersegmental nerve (Lee et al., 2004) mitotic cell cycle (Inoue et al., 2000) mitotic metaphase (Inoue et al., 2000) pCC neuron (Lee et al., 2004) presumptive embryonic/larval central nervous system (Lee et al., 2004) presumptive embryonic/larval central nervous system (with chb²) (Lee et al., 2004)
Detailed Description
	Statement Reference Homozygous and chb²/chb⁴ embryos show ectopic crossing of the midline by axons in the central nervous system. pCC axons often orient towards the midline in mutant embryos (in contrast to wild type where pCC axons extend slightly away from the midline) and sometimes crosses the midline to meet its contralateral homologue. Mutant embryos occasionally show premature arrest of the ISNb axon, at the muscle 13 cleft. (Lee et al., 2004) Mitotic defects are seen in the cells of the larval central nervous system in chb⁴/chb^S068607 flies. Polyploid metaphase figures (15%), diploid metaphase figures with hypercondensed chromosomes (4%) and circular metaphase figures (4%) are seen. The metaphase to anaphase ratio and the mitotic index is increased compared to wild type. Third instar chb⁴/chb² larvae lack imaginal discs and have a small central nervous system. More than 80% of total metaphase figures are polyploid, and more than 30% of polyploid figures have greater than an 8N chromosome complement. Circular metaphase figures and anaphase figures cannot be detected. (Inoue et al., 2000)
External Data
Linkouts
Interactions
	Show the genetic interaction network for Enhancers & Suppressors
Phenotypic Class
Enhanced by
Statement Reference chb⁴, robo¹ has neuroanatomy defective phenotype, enhanceable by lea^robo2-8 (Lee et al., 2004) chb⁴ has neuroanatomy defective phenotype, enhanceable by Abl² (Lee et al., 2004)
NOT Enhanced by
Statement Reference chb⁴, robo¹ has neuroanatomy defective phenotype, non-enhanceable by robo3¹ (Lee et al., 2004)
Enhancer of
Statement Reference chb⁴ is an enhancer of neuroanatomy defective phenotype of Abl² (Lee et al., 2004)
Suppressor of
Statement Reference chb⁴/chb⁴ is a suppressor \| partially of neuroanatomy defective phenotype of Abl^Scer\UAS.cFa, Scer\GAL4^elav.PLu (Lee et al., 2004, Lee et al., 2004)
Other
Statement Reference chb⁴, robo¹ has neuroanatomy defective phenotype (Lee et al., 2004) chb⁴, sli²/sli[+] has neuroanatomy defective phenotype (Lee et al., 2004) chb⁴, sli² has neuroanatomy defective phenotype (Lee et al., 2004) chb⁴/chb[+], robo¹ has neuroanatomy defective phenotype (Lee et al., 2004)
Phenotype Manifest In
Enhanced by
Statement Reference chb⁴, robo¹ has embryonic/larval neuron phenotype, enhanceable by lea^robo2-8 (Lee et al., 2004) chb⁴ has embryonic/larval neuron phenotype, enhanceable by Abl² (Lee et al., 2004) chb⁴ has intersegmental nerve phenotype, enhanceable by Abl² (Lee et al., 2004)
NOT Enhanced by
Statement Reference chb⁴, robo¹ has embryonic/larval neuron phenotype, non-enhanceable by robo3¹ (Lee et al., 2004)
Enhancer of
Statement Reference chb⁴ is an enhancer of embryonic/larval neuron phenotype of Abl² (Lee et al., 2004) chb⁴ is an enhancer of intersegmental nerve phenotype of Abl² (Lee et al., 2004)
Suppressor of
Statement Reference chb⁴/chb⁴ is a suppressor \| partially of intersegmental nerve phenotype of Abl^Scer\UAS.cFa, Scer\GAL4^elav.PLu (Lee et al., 2004, Lee et al., 2004)
Other
Statement Reference chb⁴, robo¹ has embryonic/larval neuron phenotype (Lee et al., 2004) chb⁴, sli²/sli[+] has embryonic/larval neuron phenotype (Lee et al., 2004) chb⁴, sli² has embryonic/larval neuron phenotype (Lee et al., 2004) chb⁴/chb[+], robo¹ has embryonic/larval neuron phenotype (Lee et al., 2004)
Additional Comments
Genetic Interactions
Statement Reference The frequency of axons ectopically crossing the midline in chb⁴ Abl² double homozygous embryos is substantially increased compared to the frequency seen in either single homozygote. chb⁴ Abl² double homozygous embryos show an increased frequency of premature arrest of the ISNb axon compared to either single homozygote, with the arrest being seen at both the muscle 6/7 and the muscle 13 choice points. sli² chb⁴ double heterozygous embryos have axons ectopically crossing the midline. capt¹⁰ chb⁴ double heterozygous embryos do not show a significant increase in axons ectopically crossing the midline compared to controls. robo¹ chb⁴ double heterozygous embryos have axons ectopically crossing the midline. Heterozygosity for lea^robo2-8 enhances the frequency of axons ectopically crossing the midline that is seen in robo¹ chb⁴ double heterozygous embryos. Heterozygosity for robo3¹ does not enhance the frequency of axons ectopically crossing the midline that is seen in robo¹ chb⁴ double heterozygous embryos. The ISNb bypass phenotype caused by expression of Abl^Scer\UAS.cFa under the control of Scer\GAL4^elav.PLu is reduced by chb⁴/chb⁴. (Lee et al., 2004)
Xenogenetic Interactions
Statement Reference
Complementation & Rescue Data
Rescued by	chb⁴/chb² is rescued by chb^{Scer\UAS.T:Avic\GFP}/Scer\GAL4^elav.PLu (Lee et al., 2004) chb⁴ is rescued by Scer\GAL4^elav.PLu/chb^Scer\UAS.cLa (Lee et al., 2004)
Comments
Stocks ( 1 )
Bloomington	24503 Df(3L)chb⁴, chb⁴/TM6B, Tb¹
Notes on Origin
Discoverer

External Crossreferences & Linkouts
Other Crossreferences

Linkouts

Synonyms & Secondary IDs ( 2 )
Reported As
Symbol Synonym	chb⁴ orbit⁴ (Lee et al., 2004, Inoue et al., 2000, )
Name Synonym
Secondary FlyBase IDs

References ( 2 )
Research paper	Lee et al., 2004, Neuron 42(6): 913--926 The microtubule plus end tracking protein Orbit/MAST/CLASP acts downstream of the tyrosine kinase Abl in mediating axon guidance. [FBrf0179303] Inoue et al., 2000, J. Cell Biol. 149(1): 153--166 Orbit, a novel microtubule-associated protein essential for mitosis in Drosophila melanogaster. [FBrf0127132]

Allele Dmel\chb4

Allele Dmel\chb⁴