Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria.
G3 (Bethesda). 2023 Aug 9;13(8). doi: 10.1093/g3journal/jkad121.
The regulatory architecture of gene expression is known to differ substantially between sexes in Drosophila, but most studies performed so far used whole-body data and only single crosses, which may have limited their scope to detect patterns that are robust across tissues and biological replicates. Here, we use allele-specific gene expression of parental and reciprocal hybrid crosses between 6 Drosophila melanogaster inbred lines to quantify cis- and trans-regulatory variation in heads and gonads of both sexes separately across 3 replicate crosses. Our results suggest that female and male heads, as well as ovaries, have a similar regulatory architecture. On the other hand, testes display more and substantially different cis-regulatory effects, suggesting that sex differences in the regulatory architecture that have been previously observed may largely derive from testis-specific effects. We also examine the difference in cis-regulatory variation of genes across different levels of sex bias in gonads and heads. Consistent with the idea that intersex correlations constrain expression and can lead to sexual antagonism, we find more cis variation in unbiased and moderately biased genes in heads. In ovaries, reduced cis variation is observed for male-biased genes, suggesting that cis variants acting on these genes in males do not lead to changes in ovary expression. Finally, we examine the dominance patterns of gene expression and find that sex- and tissue-specific patterns of inheritance as well as trans-regulatory variation are highly variable across biological crosses, although these were performed in highly controlled experimental conditions. This highlights the importance of using various genetic backgrounds to infer generalizable patterns.
已知在果蝇中,性别之间的基因表达调控结构有很大差异,但迄今为止进行的大多数研究都使用了全身数据,并且只进行了单次杂交,这可能限制了它们在检测跨组织和生物重复稳健模式的范围。在这里,我们使用 6 个黑腹果蝇近交系的亲本和相互杂交的等位基因特异性基因表达,分别在 3 个重复杂交中单独量化雌雄两性头部和性腺中的顺式和反式调控变异。我们的结果表明,雌性和雄性头部以及卵巢具有相似的调控结构。另一方面,睾丸显示出更多且明显不同的顺式调控效应,这表明之前观察到的调控结构中的性别差异可能主要源于睾丸特异性效应。我们还检查了在性腺和头部中不同性别偏倚水平下基因的顺式调控变异差异。与跨性相互关联约束表达并可能导致性拮抗的观点一致,我们发现头部中无偏倚和中度偏倚基因的顺式变异更多。在卵巢中,观察到雄性偏倚基因的顺式变异减少,这表明这些基因在雄性中的顺式变异不会导致卵巢表达的变化。最后,我们检查了基因表达的显性模式,发现性别和组织特异性的遗传模式以及反式调控变异在不同的生物杂交中高度可变,尽管这些实验是在高度受控的实验条件下进行的。这凸显了使用各种遗传背景来推断可推广模式的重要性。