title: Increased expression of X-linked genes in mammals is associated with a higher stability of transcripts and an increased ribosome density.
abstract: Mammalian sex chromosomes evolved from the degeneration of one homolog of a pair of ancestral autosomes, the proto-Y. This resulted in a gene dose imbalance that is believed to be restored (partially or fully) through upregulation of gene expression from the single active X-chromosome in both sexes by a dosage compensatory mechanism. We analyzed multiple genome-wide RNA stability data sets and found significantly longer average half-lives for X-chromosome transcripts than for autosomal transcripts in various human cell lines, both male and female, and in mice. Analysis of ribosome profiling data shows that ribosome density is higher on X-chromosome transcripts than on autosomal transcripts in both humans and mice, suggesting that the higher stability is causally linked to a higher translation rate. Our results and observations are in accordance with a dosage compensatory upregulation of expressed X-linked genes. We therefore propose that differential mRNA stability and translation rates of the autosomes and sex chromosomes contribute to an evolutionarily conserved dosage compensation mechanism in mammals.
authors: Department of Molecular Biology, Umeå University, Sweden.
authors: Marie-Line
authors: ML
authors: Faucillion
authors: Department of Molecular Biology, Umeå University, Sweden jan.larsson@molbiol.umu.se.
authors: Jan
authors: J
authors: Larsson
mesh_terms: D000818:Animals; D002460:Cell Line; D041321:Chromosomes, Human, X; D015870:Gene Expression; D050172:Genes, X-Linked; D006207:Half-Life; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D059365:Nonsense Mediated mRNA Decay; D014176:Protein Biosynthesis; D020871:RNA Stability; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D012333:RNA, Messenger
keywords: RNA half-life; RNA stability; dosage compensation; ribosome density; sex chromosomes