Data from: Molecular physiology of chemical defenses in a poison frog

Poison frogs sequester small molecule lipophilic alkaloids from their diet
of leaf litter arthropods for use as chemical defenses against predation.
Although the dietary acquisition of chemical defenses in poison frogs is
well-documented, the physiological mechanisms of alkaloid sequestration
has not been investigated. Here, we used RNA sequencing and proteomics to
determine how alkaloids impact mRNA or protein abundance in the Little
Devil Frog (Oophaga sylvatica) and compared wild caught chemically
defended frogs to laboratory frogs raised on an alkaloid-free diet. To
understand how poison frogs move alkaloids from their diet to their skin
granular glands, we focused on measuring gene expression in the
intestines, skin, and liver. Across these tissues, we found many
differentially expressed transcripts involved in small molecule transport
and metabolism, as well as sodium channels and other ion pumps. We then
used proteomic approaches to quantify plasma proteins, where we found
several protein abundance differences between wild and laboratory frogs,
including the amphibian neurotoxin binding protein saxiphilin. Finally,
because many blood proteins are synthesized in the liver, we used thermal
proteome profiling as an untargeted screen for soluble proteins that bind
the alkaloid decahydroquinoline. Using this approach, we identified
several candidate proteins that interact with this alkaloid, including
saxiphilin. These transcript and protein abundance patterns suggest the
presence of alkaloids influences frog physiology and that small molecule
transport proteins may be involved in toxin bioaccumulation in dendrobatid
poison frogs.

箭毒蛙会从其取食的地表节肢动物食谱中截留亲脂性小分子生物碱，以此作为抵御捕食者的化学防御手段。尽管箭毒蛙通过膳食获取化学防御物质的现象已被充分证实，但生物碱截留的生理机制仍未得到研究。本研究以小恶魔蛙（Oophaga sylvatica）为研究对象，利用RNA测序与蛋白质组学技术，探究生物碱如何影响其mRNA与蛋白质丰度，并将野生捕获的具备化学防御能力的蛙个体与饲喂无生物碱日粮的实验室饲养个体进行对比。为阐明箭毒蛙如何将膳食中的生物碱转运至皮肤颗粒腺，本研究重点检测了肠道、皮肤与肝脏中的基因表达情况。在这三类组织中，我们发现大量差异表达转录本参与了小分子转运与代谢过程，同时还包括钠通道及其他离子泵相关基因。随后，我们通过蛋白质组学方法对血浆蛋白进行定量分析，发现野生蛙与实验室饲养蛙之间存在多种蛋白质丰度差异，其中包括两栖类神经毒素结合蛋白saxiphilin。最后，鉴于多数血液蛋白由肝脏合成，我们采用热蛋白质组分析技术，对可与生物碱十氢喹啉（decahydroquinoline）结合的可溶性蛋白进行非靶向筛选。借助该方法，我们鉴定出多种可与该生物碱结合的候选蛋白，其中同样包括saxiphilin。上述转录本与蛋白质丰度模式表明，生物碱的存在会影响蛙类的生理状态，且小分子转运蛋白可能参与了树棘蛙科箭毒蛙的毒素生物富集过程。