RISC-loading complexes and miRISC in Drosophila melanogaster

Small RNA duplexes produced by Dicer are loaded into Argonaute proteins by RISC-loading complexes. In Drosophila the miRNA pathway uses Dicer-1 with the dsRNA-binding partner Loquacious (Loqs-PB) and loads miRNAs mainly into AGO1, whereas the siRNA pathway uses Dicer-2 with R2D2, which senses duplex asymmetry and loads siRNAs into AGO2. FlyBase also defines an alternative siRNA loading complex in which Loqs (Loqs-PD isoform) partners Dicer-2 with AGO2. Mature miRNA-loaded AGO1 associates with the GW182 protein Gawky to form the miRNA-induced silencing complex (miRISC), which represses translation and promotes deadenylation and decay of target mRNAs.

MODULE:dmel_risc_loading_complexesDRAFTCONCRETEProtein Complexmodules/dmel_risc_loading_complexes.yaml
RISC-loading complexGO:0070578 RISC complexGO:0016442
FB:FBgg0001550
FlyBase gene group RLC: Risc loading complexes
FlyBase release FB2026_03 groups 6 D. melanogaster genes as risc loading complexes (RLC); this module models that group.
FB:FBgg0001801
FlyBase gene group miRISC: Mirna-induced silencing complex
FlyBase release FB2026_03 groups 2 D. melanogaster genes as mirna-induced silencing complex (miRISC); this module models that group.
GO:0070578
RISC-loading complex
GO term grounding the module as RISC-loading complex.
GO:0016442
RISC complex
GO term grounding the module as RISC complex.

Parts follow FlyBase groups miRLC, siRLC, aRLC and miRISC. The Loqs isoform specificity (Loqs-PB in the miRNA loading complex, Loqs-PD in the alternative siRNA loading complex) cannot be expressed at gene level here. Ribonuclease III activity is given to the Dicers only. Downstream effectors of miRISC (CCR4-NOT, decapping) and the piRNA pathway are outside this module. FlyBase groups realized by this module: RLC (FBgg0001550), miRISC (FBgg0001801). Subgroups folded into it: miRLC, siRLC, aRLC. 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_risc_loading_complexes.yaml. Member genes with a gene review in this repository: loqs.

6Nodes
3Parts
1Variant Sets
2Variants
4Annotons
1Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:dmel_risc_loading_complexes 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.

  • mirna_loading → mirisc [NOT_CHECKED]

Function consistency and core coverage

0 gene-function check(s) reflected in core functions · 0 conflict(s) · 3 evidence or coverage gap(s) (3 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
mirna_loading_complex/dcr_1 Dcr-1
UniProtKB:Q9VCU9
Complex Unit 		ribonuclease III activity
GO:0004525 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
sirlc_complex/dcr_2 Dcr-2
UniProtKB:A1ZAW0
Complex Unit 		ribonuclease III activity
GO:0004525 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
arlc_complex/dcr_2 Dcr-2
UniProtKB:A1ZAW0
Complex Unit 		ribonuclease III activity
GO:0004525 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.

Gene-review completeness (1/7 grounded genes reviewed)

1 complete review(s) · 1 with deep research · 6 missing review · 0 reviewed but lacking deep research

Gene Review Complete Deep research
AGO1 A0A0B4K7Q0 ✗ — —
Dcr-2 A1ZAW0 ✗ — —
loqs Q9VJY9 ✓ ✓ ✓
gw Q8SY33 ✗ — —
Dcr-1 Q9VCU9 ✗ — —
r2d2 Q9VLW8 ✗ — —
AGO2 Q9VUQ5 ✗ — —

Details

Context
Drosophila melanogasterNCBITaxon:7227
RISC loading complexesProtein Complexdmel_risc_loading_complexes

Dicer-dsRBD protein-Argonaute loading complexes for miRNAs and siRNAs, and the AGO1-Gawky miRISC.

RISC-loading complexGO:0070578 RISC complexGO:0016442
Context
Drosophila melanogasterNCBITaxon:7227

Connections

mirna_loading -> mirisc Precedes
miRNA-loaded AGO1 leaves the loading complex and binds Gawky to form miRISC.
Part 1: miRNA duplex loading into AGO1
miRNA RISC-loading complexProtein Complexmirna_loading

Annotons

miRNA RISC-loading complex
mirna_loading_complex
Participant: Protein Complex: miRNA RISC-loading complex
Protein Complex:
miRNA RISC-loading complexGO:0070578
Active units:
AGO1
Participant: Gene Product: AGO1
Gene Product:
AGO1UniProtKB:A0A0B4K7Q0
Dcr-1
Participant: Gene Product: Dcr-1
Gene Product:
Dcr-1UniProtKB:Q9VCU9
Function:
ribonuclease III activityGO:0004525
loqs
Participant: Gene Product: loqs
Gene Product:
loqsUniProtKB:Q9VJY9

Processes

RISC complex assemblyGO:0070922
Part 2: siRNA duplex loading into AGO2
siRNA RISC-loading complexesProtein Complexsirna_loading
Variant set: R2D2 or Loqs as Dicer-2 partner (One Or More)
Dcr-2-R2D2-AGO2 siRNA RISC-loading complexProtein Complexsirlc

Annotons

Dcr-2-R2D2-AGO2 siRNA RISC-loading complex
sirlc_complex
Participant: Protein Complex: Dcr-2-R2D2-AGO2 siRNA RISC-loading complex
Protein Complex:
Dcr-2-R2D2-AGO2 siRNA RISC-loading complexGO:0070578
Active units:
AGO2
Participant: Gene Product: AGO2
Gene Product:
AGO2UniProtKB:Q9VUQ5
Dcr-2
Participant: Gene Product: Dcr-2
Gene Product:
Dcr-2UniProtKB:A1ZAW0
Function:
ribonuclease III activityGO:0004525
r2d2
Participant: Gene Product: r2d2
Gene Product:
r2d2UniProtKB:Q9VLW8

Processes

RISC complex assemblyGO:0070922
Alternative Dcr-2-Loqs-AGO2 siRNA RISC-loading complexProtein Complexarlc

Annotons

Alternative Dcr-2-Loqs-AGO2 siRNA RISC-loading complex
arlc_complex
Participant: Protein Complex: Alternative Dcr-2-Loqs-AGO2 siRNA RISC-loading complex
Protein Complex:
Alternative Dcr-2-Loqs-AGO2 siRNA RISC-loading complexGO:0070578
Active units:
AGO2
Participant: Gene Product: AGO2
Gene Product:
AGO2UniProtKB:Q9VUQ5
Dcr-2
Participant: Gene Product: Dcr-2
Gene Product:
Dcr-2UniProtKB:A1ZAW0
Function:
ribonuclease III activityGO:0004525
loqs
Participant: Gene Product: loqs
Gene Product:
loqsUniProtKB:Q9VJY9

Processes

RISC complex assemblyGO:0070922
Part 3: miRNA-guided repression of target mRNAs
miRNA-induced silencing complexProtein Complexmirisc

Annotons

miRNA-induced silencing complex
mirisc_complex
Participant: Protein Complex: miRNA-induced silencing complex
Protein Complex:
miRNA-induced silencing complexGO:0016442
Active units:
AGO1
Participant: Gene Product: AGO1
Gene Product:
AGO1UniProtKB:A0A0B4K7Q0
gw
Participant: Gene Product: gw
Gene Product:
gwUniProtKB:Q8SY33

Processes

miRNA-mediated post-transcriptional gene silencingGO:0035195