Dosage compensation and demasculinization of X chromosomes in Drosophila.
Dosage compensation and demasculinization of X chromosomes in Drosophila.
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DOI：
10.1016/j.cub.2010.06.076
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发表时间：
2010-08-24
期刊：
影响因子：
--
通讯作者：
Lockton S
中科院分区：
文献类型：
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作者：
Bachtrog D;Toda NR;Lockton S
果蝇的X染色体显示出雄性偏好表达的基因的缺陷，而哺乳动物的X染色体富集了减数分裂前表达的精子发生基因和多拷贝睾丸基因。减数分裂X失活和性对抗只能部分解释这些模式。在这里，我们提供的证据表明，剂量补偿（DC）在果蝇中可能会大大减少男性基因的X。为了平衡两性中X连锁基因和常染色体基因之间的表达，雄性果蝇超转录它们的单个X，而雌性哺乳动物沉默它们的两个X染色体中的一个。我们利用联合收割机对D.黑腹果蝇与全基因组表达谱的男性和女性，并显示大多数男性偏向基因的果蝇X染色体位于剂量补偿区以外。此外，X连锁的基因，有新获得的男性偏向表达的D。黑腹动物谱系不太可能是剂量补偿的，并且引起常染色体雄性偏向性逆转录的亲本X连锁基因更可能在补偿区域内发现。这表明果蝇中的DC有助于观察到的果蝇X染色体的去雄性化，既通过限制现有X基因的雄性偏好表达模式的出现，又通过促进雄性基因的基因运输离开X。
The X chromosome of Drosophila shows a deficiency of genes with male-biased expression, while mammalian X chromosomes are enriched for both spermatogenesis genes expressed pre-meiosis and multi-copy testis genes. Meiotic X inactivation and sexual antagonism can only partly account for these patterns. Here, we provide evidence that dosage compensation (DC) in Drosophila may contribute substantially to the depletion of male genes on the X. To equalize expression between X-linked and autosomal genes in the two sexes, male Drosophila hyper-transcribe their single X, while female mammals silence one of their two X chromosomes. We combine fine-scale mapping-data of dosage compensated regions in D. melanogaster with genome-wide expression profiles in males and females and show that most male-biased genes on the Drosophila X chromosome are located outside dosage compensated regions. Additionally, X-linked genes that have newly acquired male-biased expression in the D. melanogaster lineage are less likely to be dosage compensated, and parental X-linked genes that gave rise to an autosomal male-biased retrocopy are more likely to be found within compensated regions. This suggests that DC in Drosophila contributes to the observed demasculinization of X chromosomes in Drosophila, both by limiting the emergence of male-biased expression patterns of existing X genes, and by contributing to gene trafficking of male-genes off the X.