FlyBase Allele Report: Dmel\Sema2b[f02042]

Sema-2b^f02042 mutant third instar larvae display increased dendritic non-contacting crossing in the class I and IV dendritic arborizing (da) neurons. However, the overall morphology of axonal projections of class IV da neurons in the ventral nerve cord is normal as is the total number and morphology of epidermal cells.

Sema-2b^f02042/Df(2R)Sema-2b-C4 mutant larvae display increased dendritic non-contacting crossing in the class IV da neurons, the severity of this phenotype was intermediate between that of Sema-2b^f02042 and Df(2R)Sema-2b-C4 alone.

The proportion of enclosed (=not attached to the extracellular matrix, ECM) dendrites in the class IV da neurons is progressively increased in the Sema-2b^f02042/Df(2R)Sema-2b-C4 larvae compared to wild-type from 72hr AEL onwards. This increase is mainly due to the loss of ECM attachment in terminal dendrites.

(Meltzer et al., 2016)

In Sema-2b^f02042 homozygous pupae, 24 hours after puparium formation, the dorsolateral axon bundle is enlarged at the expense of the ventromedial bundle, shifting the average dorsolateral/ventromedial ratio to 4.77.

In Sema-2b^f02042 brains, the majority of axons for both Or92a and Or67b ORN classes take dorsolateral trajectories around the antennal lobe and terminate in specific ectopic loci in the dorsolateral antennal lobe. Residual axons that take the ventromedial trajectory terminate in approximately correct target regions. Or67d and Or88a ORN classes, correctly target the DA1 and VA1d glomeruli, respectively, in Sema-2b^f02042 brains.

The ventromedial trajectory of Or22a and Or47a-expressing axons is severely affected in Sema-2b^f02042 homozygous mutant brains. However, their glomerular targeting appears normal.

Sema-2b^f02042 Scer\FLP1^hs.PG-based MARCM clones exhibit ectopic dorsolateral trajectories and severe mistargeting.

Sema-2b^f02042 Scer\FLP1^ey.PN reverse MARCM mutants exhibit significant targeting defects in multiple ventromedial ORN classes, consistent with the idea that Sema-2b from ORNs also acts as a ligand to mediate axon-axon interactions.

In Sema-2b^f02042 paired AM29+ axon MARCM clones, both axons project dorsolaterally, implying that Sema-2b is essential for ventromedial axon pathway choice.

(Joo et al., 2013)

External Data

Linkouts

Interactions

Show genetic interaction network for Enhancers & Suppressors

Phenotypic Class

Enhanced by

Statement

Reference

Sema2b^f02042/Df(2R)Sema2b-C4 has abnormal neuroanatomy | third instar larval stage phenotype, enhanceable by trc^UAS.Tag:FLAG/Scer\GAL4^ppk.PU

(Meltzer et al., 2016)

Sema2b^f02042/Df(2R)Sema2b-C4 has abnormal neuroanatomy | third instar larval stage phenotype, enhanceable by trc^{S292A.T449A.UAS.Tag:FLAG}/Scer\GAL4^ppk.PU

(Meltzer et al., 2016)

NOT Enhanced by

Statement

Reference

Sema2b^f02042 has abnormal neuroanatomy phenotype, non-enhanceable by Sema2a⁰³⁴⁷⁴/Df(2R)A15

(Meltzer et al., 2016)

Suppressed by

Statement

Reference

Sema2b^f02042/Df(2R)Sema2b-C4 has abnormal neuroanatomy | third instar larval stage phenotype, suppressible by Scer\GAL4^ppk.PU/trc^{UAS.Tag:Myr(Src64B)}

(Meltzer et al., 2016)

Suppressor of

Statement

Reference

Sema2b^f02042 is a suppressor | partially of abnormal neuroanatomy | somatic clone phenotype of mam^k1514

(Joo et al., 2013)

Other

Statement

Reference

Sema2a⁰³⁴⁷⁴, Sema2b^f02042 has abnormal neuroanatomy phenotype

(Joo et al., 2013)

Scer\GAL4^peb-GAL4, Scer\GAL80^Orco, Sema2a⁰³⁴⁷⁴, Sema2b^3'UTR.UAS, Sema2b^f02042 has abnormal neuroanatomy phenotype

(Joo et al., 2013)

Phenotype Manifest In

Enhanced by

Statement

Reference

Sema2b^f02042/Df(2R)Sema2b-C4 has larval multidendritic class IV neuron | third instar larval stage phenotype, enhanceable by trc^UAS.Tag:FLAG/Scer\GAL4^ppk.PU

(Meltzer et al., 2016)

Sema2b^f02042/Df(2R)Sema2b-C4 has larval multidendritic class IV neuron | third instar larval stage phenotype, enhanceable by trc^{S292A.T449A.UAS.Tag:FLAG}/Scer\GAL4^ppk.PU

(Meltzer et al., 2016)

NOT Enhanced by

Statement

Reference

Sema2b^f02042 has larval multidendritic class IV neuron | third instar larval stage phenotype, non-enhanceable by Sema2a⁰³⁴⁷⁴/Df(2R)A15

(Meltzer et al., 2016)

Suppressed by

Statement

Reference

Sema2b^f02042/Df(2R)Sema2b-C4 has larval multidendritic class IV neuron | third instar larval stage phenotype, suppressible by Scer\GAL4^ppk.PU/trc^{UAS.Tag:Myr(Src64B)}

(Meltzer et al., 2016)

Sema2b^f02042/Df(2R)Sema2b-C4 has larval multidendritic class IV neuron | third instar larval stage phenotype, suppressible by mew^UAS.cMBa/mys^UAS.cDa/Scer\GAL4^ppk.PU

(Meltzer et al., 2016)

Suppressor of

Statement

Reference

Sema2b^f02042 is a suppressor | partially of olfactory receptor neuron | somatic clone phenotype of mam^k1514

(Joo et al., 2013)

Other

Statement

Reference

Sema2a⁰³⁴⁷⁴, Sema2b^f02042 has adult brain phenotype

(Joo et al., 2013)

Sema2a⁰³⁴⁷⁴, Sema2b^f02042 has antennal lobe phenotype

(Joo et al., 2013)

Sema2a⁰³⁴⁷⁴, Sema2b^f02042 has adult olfactory receptor neuron phenotype

(Joo et al., 2013)

Scer\GAL4^peb-GAL4, Scer\GAL80^Orco, Sema2a⁰³⁴⁷⁴, Sema2b^3'UTR.UAS, Sema2b^f02042 has adult brain phenotype

(Joo et al., 2013)

Scer\GAL4^peb-GAL4, Scer\GAL80^Orco, Sema2a⁰³⁴⁷⁴, Sema2b^3'UTR.UAS, Sema2b^f02042 has antennal lobe phenotype

(Joo et al., 2013)

Scer\GAL4^peb-GAL4, Scer\GAL80^Orco, Sema2a⁰³⁴⁷⁴, Sema2b^3'UTR.UAS, Sema2b^f02042 has adult olfactory receptor neuron phenotype

(Joo et al., 2013)

Additional Comments

Genetic Interactions

Statement

Reference

The increased dendritic non-contacting crossing in the class IV dendritic arborizing (da) neurons seen in Sema-2b^f02042 mutant larvae is not enhanced by the loss of Sema-2a : Sema-2b^f02042,Sema-2a⁰³⁴⁷⁴/Df(2R)A15 mutant larvae display the same amount of dendrite self-crossing as Sema-2b^f02042 mutants alone.

Expression of trc^{Scer\UAS.T:Zzzz\FLAG} under the control of Scer\GAL4^ppk.PU in the Sema-2b^f02042/Df(2R)Sema-2b-C4 mutant larvae background exacerbated the increased dendritic crossing phenotype in the class IV da neurons displayed by the Sema-2b^f02042/Df(2R)Sema-2b-C4 mutants.

Expression of trc^{S292A.T449A.Scer\UAS.T:Zzzz\FLAG} under the control of Scer\GAL4^ppk.PU in the Sema-2b^f02042/Df(2R)Sema-2b-C4 mutant larvae background exacerbated the increased dendritic crossing phenotype in the class IV da neurons displayed by the Sema-2b^f02042/Df(2R)Sema-2b-C4 mutants.

Expression of trc^{Scer\UAS.T:Myr-Src64B} under the control of Scer\GAL4^ppk.PU in the Sema-2b^f02042/Df(2R)Sema-2b-C4 mutant larvae background significantly suppressed the increased dendritic crossing phenotype in the class IV da neurons displayed by the Sema-2b^f02042/Df(2R)Sema-2b-C4 mutants.

Simultaneous expression of mew^{Scer\UAS.cMBa} and mys^Scer\UAS.cDa under the control of Scer\GAL4^ppk.PU in the Sema-2b^f02042/Df(2R)Sema-2b-C4 mutant larvae background fully rescued the increased dendritic crossing phenotype in the class IV da neurons displayed by the Sema-2b^f02042/Df(2R)Sema-2b-C4 mutants.

(Meltzer et al., 2016)

Sema-2a⁰³⁴⁷⁴ Sema-2b^f02042 double homozygous mutants exhibit ORN axon trajectory defects, with most axons projecting dorsolaterally. Expression of Sema-2b^{3'UTR.Scer\UAS} in adult ORNs, under the control of Scer\GAL4^peb-GAL4 and Scer\GAL80^Orco, in these double mutants leads to Sema-2b-expressing ORNS exhibiting three kinds of trajectory. In 15% of cases, axons are split between the dorsolateral and ventromedial trajectories. In the remaining 85% of cases, however, all axons exclusively chose either the ventromedial or dorsolateral trajectory, with nearly equal probability.

In Sema-2b^f02042, mam^k1514 double mutant paired axon clones (generated through expression of Scer\FLP1^hs.PG, Scer\GAL80^ts.αTub84B and Scer\GAL4^AM29), both neurons chose a dorsolateral axon trajectory, a phenotype opposite to that of mam^k1514 paired clones. Sema-2b removal only partially reverts the mam^k1514 phenotype in glomerular targeting, as double-mutant axons skip the DL4 glomerulus in 46% of clones despite taking the correct dorsolateral trajectory that passes by the target DL4 glomerulus.

(Joo et al., 2013)

Xenogenetic Interactions

Statement

Reference

Complementation and Rescue Data

Rescued by

Sema2b^f02042/Df(2R)Sema2b-C4 is rescued by Sema2b^UAS.cUa/Scer\GAL4^A58

(Meltzer et al., 2016)

Sema2b^f02042/Df(2R)Sema2b-C4 is rescued by Sema2b^{UAS.GFP,Tag:M(mCd8a)}/Scer\GAL4^A58

(Meltzer et al., 2016)

Sema2b^f02042 is rescued by Sema2b^{GFP,Tag:M(mCd8a)}/Scer\GAL4^peb-GAL4

(Joo et al., 2013)

Sema2b^f02042 is rescued by Sema2b^3'UTR.UAS/Scer\GAL4^peb-GAL4

(Joo et al., 2013)

Not rescued by

Sema2b^f02042/Df(2R)Sema2b-C4 is not rescued by Sema2b^UAS.cUa/Scer\GAL4^ppk.PU

(Meltzer et al., 2016)

Comments

The increased dendritic non-contacting crossing in the class IV da neurons seen in Sema-2b^f02042/Df(2R)Sema-2b-C4 mutant larvae can be rescued by ectopic expression of Sema-2b^Scer\UAS.cUa or Sema-2b^{Scer\UAS.T:Avic\GFP,T:Mmus\Cd8a} under the Scer\GAL4^A58 driver, whereas expression of Sema-2b^Scer\UAS.cUa under Scer\GAL4^ppk.PU does not rescue the phenotype.

(Meltzer et al., 2016)

Images (0)

Mutant

Wild-type

Stocks (1)

Bloomington

18505

w¹¹¹⁸; PBac{WH}Sema2b^f02042

Notes on Origin

Discoverer

External Crossreferences and Linkouts ( 0 )

Synonyms and Secondary IDs (7)

Reported As

Symbol Synonym

CG33960^f02042

CG4383^f02042

Sema-2b^f02042

Sema2b^f02042

sema-2b

(Sweeney et al., 2011)

sema-2b^f02042

(Meltzer et al., 2016)

sema2b^f02042

(Li et al., 2018)

Name Synonyms

Secondary FlyBase IDs

References (5)

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