Genomic responses to mating signals

你可能不知道“爱是否会改变一切”，但从科学上讲，交配的行为肯定会改变一切。对无脊椎动物多样化和创造性的交配习惯的研究揭示了雄性能够以惊人的方式重塑与它们交配的雌性的行为和生理。这包括雄性在交配过程中转移深入雌性大脑和神经系统以改变行为的化学物质，以及那些有效地控制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交配的雄性对雌性造成的变化是多么的全球化和复杂。我们研究了雌性果蝇与雄性果蝇交配后的反应，这些雄性果蝇在交配过程中转移了或不转移一种已知的射精‘性肽’，这种‘性肽’会影响雌性的性接受能力和产卵。我们研究了信使RNAs(制造基因产品的mRNAs)和microRNAs(位于mRNAs上并阻止它们或将其作为破坏目标的miR)在雌性受到性多肽后是如何变化的。我们发现了mRNAs的许多变化，但真正令人震惊的是不同的miR的数量。这与新兴的普遍观点一致，即MIR在调节基因如何工作方面具有极其重要和广泛的作用，据估计，所有基因的20%-30%(在果蝇中约有13,000个基因)是MIR的靶标。因此，性肽组不仅在DNA到RNA合成(转录)的水平上对雌性基因组产生整体影响，而且在RNA被翻译成蛋白质的速度上也是如此。我们对SP很感兴趣，因为它有一把‘瑞士军刀’的功能，可以改变雄性和雌性的生殖性能。值得注意的是，SP能显著提高雄鱼的繁殖性能，但对雌鱼的繁殖性能影响不大。这表明，SP在两性之争中发挥了作用，雄性可以通过最大化每次交配的回报来获益，即使这会导致其配偶的长期生殖前景下降。SP对雄性有利，因为它会在几天内降低雌性的性接受能力，并增加产卵量。因此，转移SP父亲的雄性比没有SP的雄性后代更多。然而，从长远来看，接受SP水平升高的女性会遭受不良后果。SP的作用依赖于女性的饮食，在劣质和优质食物下，SP的作用可以显著改变、废除甚至逆转。这项研究使我们能够及时解决以下两个基本问题：(1)找出男性性肽是如何干预女性基因组的--在收到性肽后，miRs以哪些关键基因为靶点？第二，鉴于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mRNAs和miRs对外部刺激的协调变化的例子，比如构成两性重要生殖功能的性肽。饮食也是女性对性多肽反应的一个重要部分，这一事实也是至关重要的，因为它允许我们在短期和长期饮食改变后在基因组SP反应的水平上进行测试。因此，我们的研究还将显示MIR在不同的饮食条件下会发生变化，这一点很重要，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.