title: X chromosome regulation of autosomal gene expression in bovine blastocysts.
abstract: Although X chromosome inactivation in female mammals evolved to balance the expression of X chromosome and autosomal genes in the two sexes, female embryos pass through developmental stages in which both X chromosomes are active in somatic cells. Bovine blastocysts show higher expression of many X genes in XX than XY embryos, suggesting that X inactivation is not complete. Here, we reanalyzed bovine blastocyst microarray expression data from a network perspective with a focus on interactions between X chromosome and autosomal genes. Whereas male-to-female ratios of expression of autosomal genes were distributed around a mean of 1, X chromosome genes were clearly shifted towards higher expression in females. We generated gene coexpression networks and identified a major module of genes with correlated gene expression that includes female-biased X genes and sexually dimorphic autosomal genes for which the sexual dimorphism is likely driven by the X genes. In this module, expression of X chromosome genes correlates with autosome genes, more than the expression of autosomal genes with each other. Our study identifies correlated patterns of autosomal and X-linked genes that are likely influenced by the sexual imbalance of X gene expression when X inactivation is inefficient.
authors.affiliation: Department of Integrative Biology & Physiology, University of California, 610 Charles E. Young Drive South, Room 1146, Los Angeles, CA, 90095-7239, USA.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Itoh
authors.forename: Arthur P
authors.initials: AP
authors.lastname: Arnold
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism*; D002417:Cattle; D005260:Female; D018507:Gene Expression Regulation, Developmental; D050172:Genes, X-Linked; D008297:Male; D014960:X Chromosome / Q000235:genetics* / Q000378:metabolism; D049951:X Chromosome Inactivation