RNA-dependent association of the Drosophila maleless protein with the male X chromosome.
BACKGROUND
Dosage compensation results in equivalent X-linked gene expression in males (XY) and females (XX). In Drosophila, both X chromosomes are active in females, and the single male X must double its transcriptional activity to allow male development. Four proteins (encoded by the male-specific lethal genes) are required for dosage compensation and associate with the X chromosome in males but not in females.


RESULTS
In this report, we focus on the maleless (MLE) protein. The MLE protein sequence contains motifs common to members of a family of RNA-dependent ATPases. We have found that association of MLE with the male X chromosome is RNase sensitive, and that mutations in the ATPase motifs affect MLE function. Overexpression of MLE or its carboxyl terminus, which includes glycine-rich repeats, reveals an RNase-sensitive affinity for all chromosome arms.


CONCLUSIONS
Our results suggest that nascent transcripts or a hypothetical RNA component of chromatin play a critical role in the biochemical mechanism of dosage compensation. The potential relationship between interaction with RNA and transcriptional control of the X chromosome suggests that the mechanism of dosage compensation is distinct from classical models for transcriptional activation.
Richter
L
L
Howard Hughes Medical Institute, Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030, USA.
Bone
J R
JR
Kuroda
M I
MI
D000251:Adenosine Triphosphatases / Q000235:genetics; D000818:Animals; D030801:Animals, Genetically Modified; D002868:Chromosomal Proteins, Non-Histone; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D004303:Dosage Compensation, Genetic; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D005260:Female; D006358:Hot Temperature; D008297:Male; D009154:Mutation; D012316:RNA Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D012259:Ribonuclease, Pancreatic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014960:X Chromosome / Q000235:genetics / Q000378:metabolism*
D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C070837:mle protein, Drosophila; D012316:RNA Nucleotidyltransferases; D012259:Ribonuclease, Pancreatic; D000251:Adenosine Triphosphatases; C027900:RNA-dependent ATPase; D004265:DNA Helicases