Incorporation of the noncoding roX RNAs alters the chromatin-binding specificity of the Drosophila MSL1/MSL2 complex.
The male-specific lethal (MSL) protein-RNA complex is required for X chromosome dosage compensation in Drosophila melanogaster. The MSL2 and MSL1 proteins form a complex and are essential for X chromosome binding. In addition, the MSL complex must integrate at least one of the noncoding roX RNAs for normal X chromosome binding. Here we find the amino-terminal RING finger domain of MSL2 binds as a complex with MSL1 to the heterochromatic chromocenter and a few sites on the chromosome arms. This binding required the same amino-terminal basic motif of MSL1 previously shown to be essential for binding to high-affinity sites on the X chromosome. While the RING finger domain of MSL2 is sufficient to increase the expression of roX1 in females, activation of roX2 requires motifs in the carboxyl-terminal domain. Binding to hundreds of sites on the X chromosome and efficient incorporation of the roX RNAs into the MSL complex require proline-rich and basic motifs in the carboxyl-terminal domain of MSL2. We suggest that incorporation of the roX RNAs into the MSL complex alters the binding specificity of the chromatin-binding module formed by the amino-terminal domains of MSL1 and MSL2.
Li
Fang
F
Centre for Functional Genomics, Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
Schiemann
Anja H
AH
Scott
Maxwell J
MJ
D000818:Animals; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D050505:Mutant Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D022661:RNA, Untranslated / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D050505:Mutant Proteins; D009687:Nuclear Proteins; D022661:RNA, Untranslated; D014157:Transcription Factors; C070837:mle protein, Drosophila; C082132:msl-1 protein, Drosophila; C094166:msl-2 protein, Drosophila; C454144:roX1 protein, Drosophila; D004265:DNA Helicases