Genomic responses to mating signals

你可能不知道“爱是否能改变一切”，但从科学角度来说，交配行为确实能改变一切。研究集中在无脊椎动物多样的和创造性的交配习惯上，揭示了雄性可以以惊人的方式重塑与之交配的雌性的行为和生理。这包括雄性在交配过程中传递的化学物质，这些化学物质会深入到雌性的大脑和神经系统，从而改变它们的行为，以及那些有效地接管雌性生殖系统的化学物质。难怪女性有时会抵制这种操纵。我们最近的研究揭示了雄性交配对雌性的影响是多么全球性和复杂。我们研究了雌性果蝇的反应，雄性果蝇在交配过程中是否转移了一种“性肽”，这种“性肽”会影响雌性的性接受能力和产卵能力。我们研究了信使rna （mRNAs，制造基因产物）和微小rna （miRs，位于mrna上并阻断它们或以破坏它们为目标）在接受性肽后在女性体内的变化。我们发现了mrna的许多变化，但真正令人震惊的是mir的数量发生了变化。这与新出现的普遍观点一致，即miRs在调节基因的工作方式方面具有极其重要和广泛的作用，据估计，所有基因中有20-30%（果蝇中大约有13,000个基因）是miRs的靶标。因此，性肽不仅在DNA到RNA合成（转录）的水平上，而且在RNA翻译（即制造成蛋白质）的速度上，对女性基因组产生了全球性的影响。我们对SP感兴趣，因为它具有“瑞士军刀”的功能，可以改变男性和女性的生殖表现。值得注意的是，SP可以显著提高雄性的生殖性能，而牺牲雌性的生殖性能。这表明SP在两性之战中发挥了作用，雄性可以通过最大化每次交配的回报来获利，即使这会导致其配偶长期繁殖前景的下降。SP对雄性有益，因为它会在几天内降低雌性的性接受能力，增加产卵量。因此，传递SP的雄性比缺乏SP的雄性生育更多的后代。然而，从长远来看，接受高水平SP的雌性会遭受不良后果。SP的作用依赖于女性的饮食，在低质量和高质量的食物下，SP的作用可以显著改变、消除甚至逆转。这项研究使我们能够及时地解决以下两个基本问题：(1)找出男性性肽如何干预女性基因组-哪些是miRs在接收性肽后靶向的关键基因？其次，考虑到女性的饮食是决定女性对性肽有多少反应的关键，(2)研究女性基因组在饮食的短期和长期（进化）变化后对性肽的反应。这项研究很重要，因为这是我们第一个可以研究mrna和miRs在外部刺激下协同变化的例子，比如性肽，它是两性重要生殖功能的基础。饮食也是女性对性肽反应的重要组成部分，这一事实也至关重要，因为它使我们能够在短期和长期改变饮食后测试基因组SP反应的水平。因此，我们的研究也将表明，mir在不同的饮食条件下会发生变化，这很重要，因为饮食也是寿命的关键决定因素。

You may not know whether 'love changes everything', but, scientifically speaking, the act of mating certainly does. Research focussed on the varied and inventive mating habits of invertebrates reveals the astonishing ways in which males can remodel the behaviour and physiology of the females with which they mate. This includes the transfer during mating by males of chemicals that go deep into female brains and nervous systems to alter behaviour, and those that effectively take over the female reproductive system. Small wonder then that females are sometimes resistant to such manipulations. Our recent work reveals just how global and sophisticated are the changes wrought upon females by mating males. We examined the responses of female fruitflies that mated with males that either did or did not transfer during mating a single ejaculate 'sex peptide' known to affect female sexual receptivity and egg laying. We examined both how messenger RNAs (mRNAs, that make gene products), and microRNAs (miRs, which sit on mRNAs and block them or target them for destruction) changed in females following receipt of sex peptide. We found many alterations to mRNAs, but what was really striking was the number of miRs that were different. This is consistent with the emerging general view that miRs have extremely important and widespread roles in regulating how genes work, with 20-30% of all genes (roughly 13,000 genes in the fruitfly) estimated as targets for miRs. Hence sex peptide sets in train global effects on female genomes not only at the level of DNA to RNA synthesis (transcription), but also on the rate at which RNA is translated (i.e. made into proteins). We are interested in SP because it has a 'swiss army knife' of functions and can alter the reproductive performance of both males and females. Remarkably, SP can significantly benefit the reproductive performance of males at the expense of that of females. This shows that SP plays a role in the battle of the sexes, where males can gain by maximising their returns from each mating even if that results in a decrease in the longer term reproductive prospects of their mates. SP benefits males because it decreases female sexual receptivity for several days and increases egg-laying. Hence males that transfer SP father more offspring than males that lack SP. However, females that receive elevated levels of SP suffer adverse consequences in the long term. The effects of SP are dependent on female diet and can be significantly altered, abolished or even reversed in sign under poor and good quality food. This research puts us in a timely position to address the following two fundamental questions: (1) to find out how male sex peptide intervenes in the female genome - which are the key genes that are targeted by miRs following receipt of sex peptide? and secondly - given that female diet is key to determining how much females are able to respond to sex peptide - (2) to examine how female genomes respond to sex peptide following both short- and long-term (evolutionary) changes in diet. The research is important because this is the first example we have where we can investigate the co-ordinated changes in both mRNAs and miRs to an external stimulus like the sex peptide that underlies important reproductive functions in both sexes. The fact that diet is also an important part of how females respond to sex peptide is also crucial as it allows us to test at the level of the genome SP responses following both short- and long-term alterations to diet. Our research will also therefore show miRs that change under different dietary conditions, which is important because diet is also a crucial determinant of lifespan.