FB2026_03 , released September 17, 2026
Physical Interaction report
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General Information
Interaction Type
Interacting Genes
FlyBase ID
FBig0000103291
Interaction Network
Interactions Browser links
Sxl network
tra network
Reported Interactions
FBrf0059127-1.EMSA.A
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
Sxl 

Sxl

bait

GST tag

tra 

tra

prey

[32]P label

tra 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
tra 
non-sex specific intron
sufficient binding region
TTTTGTTGTTTTTTTTCTAGTGTC
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Interaction in vitro; bait produced as a recombinant fusion protein in bacterial system; prey produced and labeled by in vitro transcription.

Sxl binds to the non-sex-specific intron of tra, blocking splicing at this site and promoting usage of the less active female-specific splice site upstream.

FBrf0059127-2a.XL.A
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
tra 

tra

bait

[32]P label

tra 
Sxl 

Sxl

prey

GST tag

Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
tra 
non-sex specific intron
sufficient binding region
UUUUGUUGUUUUUUUUCUAGUGUC
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Interaction in vitro; bait produced and labeled by in vitro transcription; prey produced as a recombinant fusion protein in bacterial system.

Sxl and U2af65 compete for binding to the non-sex-specific intron of tra. Binding of Sxl to the non-sex-specific intron blocks U2AF and promotes usage of the lower affinity female-specific splice site upstream.

RNA-bound protein was UV crosslinked, separated by SDS-PAGE and the molecular weight of the bound protein was visualized by autoradiography.

FBrf0210202-13.coIP.PCR
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
Sxl 

Sxl

bait
tra 

tra

prey
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Source was embryos of wild-type fly line; bait produced from endogenous gene; prey produced from endogenous gene.

FBrf0241006-7.coIP.PCR
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
Sxl 

Sxl

bait
tra 

tra

prey
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Source was embryos of wild-type flies; bait produced from endogenous gene; prey produced from endogenous gene.

Positive control.

FBrf0249042-1.EMSA.A
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
Sxl 

Sxl

bait

GST tag

tra 

tra

prey

[32]P label

tra 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
tra 
Sxl-binding site
sufficient binding region
UUUUUGUUGUUUUUUUU

non-sex-specific polypyrimidine-tract 3 prime splice site of tra.

Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

positive control

Interaction in vitro; bait produced as a recombinant fusion protein in bacterial system; prey produced and labeled by in vitro transcription.

External Crossreferences and Linkouts ( 1 )
Linkouts
MIST - An integrated Molecular Interaction Database
References (4)