Lifting a chromosome:: dosage compensation in Drosophila melanogaster

Twofold differences in gene expression levels can be vital for organism. This is beautifully illustrated by the process of 'dosage compensation' in Drosphila, which doubles transcription from the single male X chromosome to equal the mRNA levels originating from the two X chromosomes in female cells. Failure of the process leads to male-specific lethality. A number of recent publications have furthered our understanding of the ribonucleoprotein complex, which mediates dosage compensation and how it targets the male chromosome recognition and the nature of the principles of X chromosome configuration, that allows fine-tuning of transcription, remain the most interesting challenges. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.