module: dmel_msl_dosage_compensation_complex
title: MSL dosage compensation complex in Drosophila melanogaster
label: MSL complex
module_type: PROTEIN_COMPLEX
description: >-
  The male-specific lethal (MSL) complex doubles transcription of the single
  X chromosome in males. It contains five proteins, MSL1, MSL2, MSL3, the
  acetyltransferase MOF and the RNA helicase MLE, and one of two long
  noncoding RNAs, roX1 or roX2, which are redundant. MSL2 is made only in
  males and nucleates assembly; MLE remodels the roX RNAs to incorporate them.
  The complex binds high-affinity sites on the X and spreads to active genes,
  where MOF acetylates histone H4 lysine 16 to raise transcription.
summary: >-
  Male-specific MSL proteins and roX RNAs that acetylate H4K16 on the male X
  to upregulate its transcription.
concepts:
  - {id: GO:0072487, label: MSL complex}
cellular_components:
  - {id: GO:0000805, label: X chromosome}
parts:
  - id: msl_protein_core
    label: MSL protein subunits
    role: X-targeting and H4K16 acetylation
    genes: [msl-1, msl-2, msl-3, mof, mle]
    processes:
      - {id: GO:0009047, label: dosage compensation by hyperactivation of X chromosome}
    unit_functions:
      mof: {id: GO:0046972, label: histone H4K16 acetyltransferase activity}
      msl-2: {id: GO:0061630, label: ubiquitin protein ligase activity}
      mle: {id: GO:0003724, label: RNA helicase activity}
  - id: rox_rnas
    label: roX long noncoding RNAs
    role: RNA subunits
    module_type: MODULE
    variant_sets:
      - id: rox_variants
        label: roX1 or roX2
        selection: ONE_OR_MORE
        variants:
          - {id: rox1, label: roX1 RNA, module_type: MODULE, genes: ["lncRNA:roX1"]}
          - {id: rox2, label: roX2 RNA, module_type: MODULE, genes: ["lncRNA:roX2"]}
notes: >-
  The roX RNAs have no protein product and are grounded to their FlyBase gene
  ids; their nodes are typed MODULE, because the schema has no RNA or
  ribonucleoprotein node type and PROTEIN_COMPLEX would misdescribe a single
  lncRNA. MSL2 ubiquitin ligase activity (toward histone H2B and the complex's own
  subunits) is recorded with the general ubiquitin protein ligase term.