A stable proteinaceous structure in the territory of inactive X chromosomes.
Transcriptional inactivation of one copy of the X chromosome in female cells equalizes expression of X-linked genes between males and females. This "dosage compensation" is a multistep process that involves epigenetic modifications of chromatin and is induced by the expression of a large non-coding RNA termed Xist. In contrast to protein-coding mRNA molecules, which are free to diffuse and roam the entire nuclear interior, Xist is locally constrained to the territory of inactive X chromosomes by as yet unclear mechanisms. Recent results have suggested a contribution of scaffold attachment factor A (SAF-A) in the silencing of X-linked genes, maybe by inducing a local change in nuclear architecture. Here, in vivo mobility experiments demonstrate that SAF-A is a component of a highly stable proteinaceous structure in the territory of inactive X chromosomes, which might act as a platform for immobilizing Xist RNA during the maintenance phase of X inactivation.
Fackelmayer
Frank O
FO
Department of Molecular Cell Biology, Heinrich-Pette-Institute, Martinistrasse 52, 20251 Hamburg, Germany. frank@fackelmayer.de
D002460:Cell Line; D041321:Chromosomes, Human, X; D004303:Dosage Compensation, Genetic; D005260:Female; D006801:Humans; D008856:Microscopy, Fluorescence; D011506:Proteins / Q000737:chemistry*; D014162:Transfection
D011506:Proteins