title: Dosage compensation and inverse effects in triple X metafemales of Drosophila.
abstract: Dosage compensation, the equalized X chromosome gene expression between males and females in Drosophila, has also been found in triple X metafemales. Inverse dosage effects, produced by genomic imbalance, are believed to account for this modulated expression, but they have not been studied on a global level. Here, we show a global expression comparison of metafemales (XXX; AA) with normal females (XX; AA) with high-throughput RNA-sequencing. We found that the majority of the X-linked genes in metafemales exhibit dosage compensation with an expression level similar to that of normal diploid females. In parallel, most of the autosomal genes were expressed at about two-thirds the level of normal females, the ratio of inverse dosage effects produced by the extra X chromosome. Both compensation and inverse effects were further confirmed by combination of X-linked and autosomally located miniwhite reporter genes in metafemales and relative quantitative PCR of selected genes. These data provide evidence for an inverse dosage component to X chromosome compensation.
authors.affiliation: Division of Biological Sciences, Computer Science Department, and Informatics Institute, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Lin
authors.initials: L
authors.lastname: Sun
authors.forename: Adam F
authors.initials: AF
authors.lastname: Johnson
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Donohue
authors.forename: Jilong
authors.initials: J
authors.lastname: Li
authors.forename: Jianlin
authors.initials: J
authors.lastname: Cheng
authors.forename: James A
authors.initials: JA
authors.lastname: Birchler
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D004303:Dosage Compensation, Genetic; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D017930:Genes, Reporter; D008297:Male; D016133:Polymerase Chain Reaction; D015203:Reproducibility of Results; D017423:Sequence Analysis, RNA; D014960:X Chromosome / Q000235:genetics*