Abundance of female-biased and paucity of male-biased somatically expressed genes on the mouse X-chromosome
2012 (English)In: BMC Genomics, ISSN 1471-2164, Vol. 13, 607- p.Article in journal (Refereed) Published
Empirical evaluations of sexually dimorphic expression of genes on the mammalian X-chromosome are needed to understand the evolutionary forces and the gene-regulatory mechanisms controlling this chromosome. We performed a large-scale sex-bias expression analysis of genes on the X-chromosome in six different somatic tissues from mouse.
Our results show that the mouse X-chromosome is enriched with female-biased genes and depleted of male-biased genes. This suggests that feminisation as well as de-masculinisation of the X-chromosome has occurred in terms of gene expression in non-reproductive tissues. Several mechanisms may be responsible for the control of female-biased expression on chromosome X, and escape from X-inactivation is a main candidate. We confirmed escape in case of Tmem29 using RNA-FISH analysis. In addition, we identified novel female-biased non-coding transcripts located in the same female-biased cluster as the well-known coding X-inactivation escapee Kdm5c, likely transcribed from the transition-region between active and silenced domains. We also found that previously known escapees only partially explained the overrepresentation of female-biased X-genes, particularly for tissue-specific female-biased genes. Therefore, the gene set we have identified contains tissue-specific escapees and/or genes controlled by other sexually skewed regulatory mechanisms. Analysis of gene age showed that evolutionarily old X-genes (>100 myr, preceding the radiation of placental mammals) are more frequently female-biased than younger genes.
Altogether, our results have implications for understanding both gene regulation and gene evolution of mammalian X-chromosomes, and suggest that the final result in terms of the X-gene composition (masculinisation versus feminisation) is a compromise between different evolutionary forces acting on reproductive and somatic tissues.
Place, publisher, year, edition, pages
2012. Vol. 13, 607- p.
X-chromosome, Sex chromosome; Somatic; Gene expression; Sexual antagonism; Sexual selection; Gender; Sex-bias; Female-bias; Male-bias; Sexual dimorphism; Dosage compensation; X-inactivation; Escape; Feminisation; Masculinisation; De-masculinisation; Microarray; Non-coding RNA; lncRNA; Tmem29; Kdm5c; Xist
Research subject Genetics; Biology with specialization in Animal Development; Biology with specialization in Molecular Biology
IdentifiersURN: urn:nbn:se:uu:diva-191574DOI: 10.1186/1471-2164-13-607ISI: 000312959100001OAI: oai:DiVA.org:uu-191574DiVA: diva2:585872