module: dmel_pirna_nuclear_complexes
title: Nuclear piRNA pathway complexes (RDC and PICTS) in Drosophila melanogaster
label: Nuclear piRNA pathway complexes
module_type: PROTEIN_COMPLEX
description: >-
  Two nuclear complexes act in the Drosophila germline piRNA pathway. The
  Rhino-Deadlock-Cutoff (RDC) complex binds dual-strand piRNA clusters, where
  the HP1 paralog Rhino recognises H3K9me3, and licenses non-canonical
  transcription of cluster precursors that are processed into piRNAs. The
  Panoramix-induced co-transcriptional silencing complex (PICTS, also called
  SFiNX), made of Panoramix, Nxf2, Nxt1 and dynein light chain Ctp, is
  recruited by piRNA-guided Piwi to nascent transposon transcripts and
  triggers H3K9 methylation and heterochromatin formation over the target.
summary: >-
  RDC, which drives piRNA cluster transcription, and PICTS/SFiNX, which
  silences piRNA-targeted transposons co-transcriptionally.
concepts:
  - {id: GO:0140966, label: piRNA-mediated heterochromatin formation}
cellular_components:
  - {id: GO:0000785, label: chromatin}
parts:
  - id: rdc_complex
    label: Rhino-Deadlock-Cutoff complex
    role: piRNA cluster transcription
    group: RDC
    complex_term: {id: GO:1990469, label: Rhino-Deadlock-Cutoff Complex}
    processes:
      - {id: GO:0140541, label: piRNA transcription}
  - id: picts_complex
    label: Panoramix-induced co-transcriptional silencing complex
    role: co-transcriptional transposon silencing
    group: PICTS
    processes:
      - {id: GO:0141006, label: transposable element silencing by piRNA-mediated heterochromatin formation}
notes: >-
  The two FlyBase groups act at different steps (piRNA production versus
  piRNA-guided silencing) and are linked only through piRNAs and Piwi, which
  are not modelled here; no direct connection is asserted. Ctp (dynein light
  chain LC8) also has many cytoplasmic roles; here it is the PICTS dimerising
  subunit. The module concept is the overall nuclear piRNA heterochromatin
  pathway that both complexes serve.
function_note: >-
  No molecular function is assigned in this version: the Rhino-Deadlock-Cutoff
  and Panx-Nxf2-Nxt1-Ctp complexes act as chromatin and RNA adaptors, and the
  binding terms their subunits carry in GOA (piRNA cluster binding for Cutoff,
  piRNA binding for Panx, chromatin-protein adaptor activity for Nxf2) are not
  yet used as annoton functions.