The MRG domain mediates the functional integration of MSL3 into the dosage compensation complex.
The male-specific-lethal (MSL) proteins in Drosophila melanogaster serve to adjust gene expression levels in male flies containing a single X chromosome to equal those in females with a double dose of X-linked genes. Together with noncoding roX RNA, MSL proteins form the "dosage compensation complex" (DCC), which interacts selectively with the X chromosome to restrict the transcription-activating histone H4 acetyltransferase MOF (males-absent-on-the-first) to that chromosome. We showed previously that MSL3 is essential for the activation of MOF's nucleosomal histone acetyltransferase activity within an MSL1-MOF complex. By characterizing the MSL3 domain structure and its associated functions, we now found that the nucleic acid binding determinants reside in the N terminus of MSL3, well separable from the C-terminal MRG signatures that form an integrated domain required for MSL1 interaction. Interaction with MSL1 mediates the activation of MOF in vitro and the targeting of MSL3 to the X-chromosomal territory in vivo. An N-terminal truncation that lacks the chromo-related domain and all nucleic acid binding activity is able to trigger de novo assembly of the DCC and establishment of an acetylated X-chromosome territory.
Adolf-Butenandt-Institut, Molekularbiologie, Schillerstr. 44, 80336 München, Germany.
Violette
V
Morales
Catherine
C
Regnard
Annalisa
A
Izzo
Irene
I
Vetter
Peter B
PB
Becker
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D029721:Drosophila Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D051548:Histone Acetyltransferases; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014960:X Chromosome / Q000737:chemistry / Q000378:metabolism*
D029721:Drosophila Proteins; D009687:Nuclear Proteins; C092595:Pabp2 protein, Drosophila; D016601:RNA-Binding Proteins; D014157:Transcription Factors; C082132:msl-1 protein, Drosophila; C093904:msl-3 protein, Drosophila; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; C111063:mof protein, Drosophila