Equalizing the sexes
Two independent research papers in the February 1 issue of G&D reveal that the Drosophila UNR protein is a novel regulator of X-chromosome dosage compensation in flies. Dosage compensation is the equalization of X-linked gene expression between males (which have one X chromosome in flies) and females (which have two X chromosomes in flies). Fruit flies accomplish this by increasing transcription of the single male X chromosome two-fold. Transcriptional upregulation of the Dros. male X chromosome is facilitated by the Dosage Compensation Complex (DCC). The DCC fails to assemble in female flies because a key subunit, male-specific lethal 2 (msl-2), is not produced.
Previous work identified the sex-lethal protein (dSXL) as a necessary repressor of msl-2 translation. New work from the labs of Drs. Fatima Gebauer (CRG-UPF) and Matthias Hentze (EMBL) identify the Drosophila homolog of the mammalian UNR protein as a co-factor required for SXL-mediated repression of msl-2 translation.
Dr. Gebauer points out that the "UNR is, therefore, an essential component of a translational control mechanism that prevents dosage compensation in female cells," and Dr. Hentze adds that "These new studies teach us how a protein that is expressed in both sexes can be used for an essential female-specific function. Learning more about how dSXL and UNR work together will instruct us on how cells control the key step of protein synthesis."
By John M. Grohol, Psy.D. on
21 Feb 2009
Published on PsychCentral.com. All rights reserved.
People are like stained-glass windows. They sparkle and shine when the sun is out, but when the darkness sets in, their true beauty is revealed only if there is a light from within.
-- Elizabeth Kubler-Ross