Animals that use venom to feed on a wide diversity of prey may evolve a complex mixture of toxins to target a variety of physiological processes and prey-defense mechanisms. Blarina brevicauda, the northern-short tailed shrew, is one of few venomous mammals, and is also known to eat evolutionarily divergent prey. Despite their complex diet, earlier proteomic and transcriptomic studies of this shrew’s venom have only identified two venom proteins. Here, we investigated with comprehensive molecular approaches whether B. brevicauda venom is more complex than previously understood. We generated de novo assemblies of a B. brevicauda genome and submaxillary-gland transcriptome, as well as sequenced the salivary proteome. Our findings show that B. brevicauda’s venom composition is simple relative to their broad diet and is likely limited to seven proteins from six gene families. Additionally, we explored expression levels and rate of evolution of these venom genes and the origins of key duplications that led to toxin neofunctionalization. We also found three proteins that may be involved in endogenous self-defense. The possible synergism of the toxins suggests that vertebrate prey may be the main target of the venom. Further functional assays for all venom proteins on both vertebrate and invertebrate prey would provide further insight into the ecological relevance of venom in this species.

中文翻译：

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全面的多组学方法可揭示出饮食综合专家北部短尾Sh Blarina brevicauda中相对简单的毒液。

使用毒液捕食种类繁多的猎物的动物可能会进化出复杂的毒素混合物，以针对各种生理过程和猎物防御机制。Blarina brevicauda是北方短尾northern，是少数有毒哺乳动物之一，并且以进食进化上不同的猎物而著称。尽管饮食复杂，对该sh毒液的早期蛋白质组学和转录组学研究仅鉴定出两种毒液蛋白。在这里，我们用全面的分子方法研究了短双歧杆菌短毒素是否比以前理解的更复杂。我们生成了短双歧杆菌的从头组装基因组和上颌下腺转录组，以及唾液蛋白质组测序。我们的发现表明，短双歧杆菌的毒液成分相对于其广泛的饮食而言很简单，并且可能仅限于六个基因家族中的七个蛋白质。此外，我们探索了这些毒液基因的表达水平和进化速率，以及导致毒素新功能化的关键重复的起源。我们还发现了三种可能与内源性自卫有关的蛋白质。毒素可能的协同作用表明脊椎动物的猎物可能是毒液的主要目标。对脊椎动物和无脊椎动物猎物上所有毒液蛋白进行进一步的功能测定，将进一步了解该毒液在该物种中的生态意义。