Structure-function analysis of the RNA helicase maleless.
Loss of function of the RNA helicase maleless (MLE) in Drosophila melanogaster leads to male-specific lethality due to a failure of X chromosome dosage compensation. MLE is presumably involved in incorporating the non-coding roX RNA into the dosage compensation complex (DCC), which is an essential but poorly understood requirement for faithful targeting of the complex to the X chromosome. Sequence comparison predicts several RNA-binding domains in MLE but their properties have not been experimentally verified. We evaluated the RNA-binding characteristics of these conserved motifs and their contributions to RNA-stimulated ATPase activity, to helicase activity, as well as to the targeting of MLE to the nucleus and to the X chromosome territory. We find that RB2 is the dominant, conditional RNA-binding module, which is indispensable for ATPase and helicase activity whereas the N-terminal RB1 motif does not bind RNA, but is involved in targeting MLE to the X chromosome. The C-terminal domain containing a glycine-rich heptad repeat adds potential dimerization and RNA-binding surfaces which are not required for helicase activity.
Izzo
Annalisa
A
Adolf-Butenandt-Institut and Center of integrated Protein Science, München, Germany.
Regnard
Catherine
C
Morales
Violette
V
Kremmer
Elisabeth
E
Becker
Peter B
PB
D000227:Adenine Nucleotides / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004265:DNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000201:enzymology*; D009154:Mutation; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry / Q000378:metabolism; D020365:RNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014960:X Chromosome / Q000737:chemistry
D000227:Adenine Nucleotides; D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D014157:Transcription Factors; C070837:mle protein, Drosophila; D012313:RNA; D000251:Adenosine Triphosphatases; D004265:DNA Helicases; D020365:RNA Helicases