mRNA nuclear export machinery in Drosophila melanogaster

Bulk export of mRNA from the nucleus is coupled to transcription and processing. The TREX complex, consisting of the THO subcomplex with the DEAD-box helicase Hel25E (UAP56) and the adaptor Ref1 (ALY), is loaded onto nascent mRNA and hands it to the export receptor heterodimer formed by sbr (NXF1) and Nxt1, which carries the mRNP through the nuclear pore complex by interacting with FG-repeat nucleoporins. TREX-2 (xmas, PCID2 and e(y)2) associates with the nuclear pore and couples transcription with export; in Drosophila it links actively transcribed genes to the nuclear periphery and shares e(y)2 with the SAGA deubiquitinase module.

MODULE:dmel_mrna_nuclear_exportDRAFTCONCRETEBiological Processmodules/dmel_mrna_nuclear_export.yaml
mRNA export from nucleusGO:0006406
FB:FBgg0000601
FlyBase gene group THO-C: Tho complex
FlyBase release FB2026_03 groups 5 D. melanogaster genes as tho complex (THO-C); this module models that group.
FB:FBgg0000603
FlyBase gene group TREX: Transcription export complex
FlyBase release FB2026_03 groups 8 D. melanogaster genes as transcription export complex (TREX); this module models that group.
FB:FBgg0000605
FlyBase gene group TREX-2: Transcription export complex-2
FlyBase release FB2026_03 groups 3 D. melanogaster genes as transcription export complex-2 (TREX-2); this module models that group.
FB:FBgg0001972
FlyBase gene group NXF: Nxf1-nxt1 mrna nuclear export factor complex
FlyBase release FB2026_03 groups 2 D. melanogaster genes as nxf1-nxt1 mrna nuclear export factor complex (NXF); this module models that group.
GO:0006406
mRNA export from nucleus
GO term grounding the module as mRNA export from nucleus.

Boundary. FlyBase's THO-C group is entirely contained in TREX and is represented through the TREX part. Nuclear pore complex proteins, the exon junction complex and SAGA are outside the module. GO has no cellular-component term for the Nxf1-Nxt1 heterodimer, so that part has no complex term. FlyBase groups realized by this module: THO-C (FBgg0000601), TREX (FBgg0000603), TREX-2 (FBgg0000605), NXF (FBgg0001972). Participants were generated from the FlyBase gene-group membership and mapped to UniProtKB by projects/FLYBASE_GENE_GROUPS/generate_modules.py from module_specs/dmel_mrna_nuclear_export.yaml. None of the member genes has a gene review in this repository yet.

4Nodes
3Parts
0Variant Sets
0Variants
3Annotons
1Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:dmel_mrna_nuclear_export deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Reaction chaining (advisory)

✓ every PRECEDES step chains, or its break is acknowledged via chaining_status.

  • trex → nxf1_nxt1 [NOT_CHECKED]

Function consistency and core coverage

0 gene-function check(s) reflected in core functions · 0 conflict(s) · 1 evidence or coverage gap(s) (1 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
trex_complex/hel25e Hel25E
UniProtKB:Q27268
Complex Unit 		RNA helicase activity
GO:0003724 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.

Gene-review completeness (0/13 grounded genes reviewed)

0 complete review(s) · 0 with deep research · 13 missing review · 0 reviewed but lacking deep research

Gene Review Complete Deep research
tho2 E2QCS8 ✗ — —
Hel25E Q27268 ✗ — —
thoc7 Q8IRJ8 ✗ — —
sbr Q9U1H9 ✗ — —
xmas Q9U3V9 ✗ — —
Ref1 Q9V3E7 ✗ — —
Nxt1 Q9V3H8 ✗ — —
tex Q9VHT2 ✗ — —
Hpr1 Q9VNI8 ✗ — —
PCID2 Q9VTL1 ✗ — —
thoc6 Q9VTV1 ✗ — —
e(y)2 Q9VYX1 ✗ — —
thoc5 Q9W1F4 ✗ — —

Details

Context
Drosophila melanogasterNCBITaxon:7227
nucleusGO:0005634
mRNA nuclear exportBiological Processdmel_mrna_nuclear_export

TREX, TREX-2 and the Nxf1-Nxt1 receptor, which package and move mRNA out of the nucleus.

mRNA export from nucleusGO:0006406
Context
Drosophila melanogasterNCBITaxon:7227
nucleusGO:0005634

Connections

trex -> nxf1_nxt1 Precedes
TREX loads the Nxf1-Nxt1 receptor onto the processed mRNP.
Part 1: mRNP packaging for export
Transcription export complexBiological Processtrex

THO (Hpr1, tho2, thoc5, thoc6, thoc7) with Hel25E, Ref1 and tex (the Tex1 homolog).

Annotons

Transcription export complex
trex_complex
Participant: Protein Complex: Transcription export complex
Protein Complex:
Transcription export complexGO:0000346
Active units:
Hel25E
Participant: Gene Product: Hel25E
Gene Product:
Hel25EUniProtKB:Q27268
Function:
RNA helicase activityGO:0003724
Hpr1
Participant: Gene Product: Hpr1
Gene Product:
Hpr1UniProtKB:Q9VNI8
Ref1
Participant: Gene Product: Ref1
Gene Product:
Ref1UniProtKB:Q9V3E7
tex
Participant: Gene Product: tex
Gene Product:
texUniProtKB:Q9VHT2
tho2
Participant: Gene Product: tho2
Gene Product:
tho2UniProtKB:E2QCS8
thoc5
Participant: Gene Product: thoc5
Gene Product:
thoc5UniProtKB:Q9W1F4
thoc6
Participant: Gene Product: thoc6
Gene Product:
thoc6UniProtKB:Q9VTV1
thoc7
Participant: Gene Product: thoc7
Gene Product:
thoc7UniProtKB:Q8IRJ8
Part 2: mRNP translocation through the nuclear pore
Nxf1-Nxt1 export receptorBiological Processnxf1_nxt1

Annotons

Nxf1-Nxt1 export receptor
nxf1_nxt1_complex
Participant: Protein Complex: Nxf1-Nxt1 export receptor
Protein Complex:
Nxf1-Nxt1 export receptor
Active units:
Nxt1
Participant: Gene Product: Nxt1
Gene Product:
Nxt1UniProtKB:Q9V3H8
sbr
Participant: Gene Product: sbr
Gene Product:
sbrUniProtKB:Q9U1H9
Part 3: nuclear pore-associated export and gene gating
Transcription export complex 2Biological Processtrex2

Annotons

Transcription export complex 2
trex2_complex
Participant: Protein Complex: Transcription export complex 2
Protein Complex:
Transcription export complex 2GO:0070390
Active units:
PCID2
Participant: Gene Product: PCID2
Gene Product:
PCID2UniProtKB:Q9VTL1
e(y)2
Participant: Gene Product: e(y)2
Gene Product:
e(y)2UniProtKB:Q9VYX1
xmas
Participant: Gene Product: xmas
Gene Product:
xmasUniProtKB:Q9U3V9