Nucleic Acids Research Advance Access originally published online on December 17, 2007
Nucleic Acids Research 2008 36(3):950-962; doi:10.1093/nar/gkm1108
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Nucleic Acids Research, 2008, Vol. 36, No. 3 950-962
© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Nucleic Acid Enzymes |
Structure-function analysis of the RNA helicase maleless
1Adolf-Butenandt-Institut and Center of integrated Protein Science, München, Germany and 2institute for Molecular Immunology, GSF, 81377 München, Germany
*To whom correspondence should be addressed. Tel: +89 2180 75427; Fax: +89 2180 75425; Email: pbecker{at}med.uni-muenchen.de
Received August 4, 2007. Revised November 26, 2007. Accepted November 27, 2007.
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.
Present addressess: Annalisa Izzo, Max Planck Institute for Immunology, 79279 Freiburg, Germany. Violette Morales, LBME, CNRS UMR 5099 - IFR 109, 118 Route de Narbonne, 31062 Toulouse Cedex, France.