Correa-Garhwal Sandra M, Chaw R Crystal, Clarke Thomas H, Ayoub Nadia A, Hayashi Cheryl Y
Department of Biology, University of California, Riverside, CA 92521, USA.
Department of Biology, University of California, Riverside, CA 92521, USA; Department of Biology, Washington and Lee University, Lexington, VA 24450, USA; J. Craig Venter Institute, Rockville, MD 20850, USA.
Zoology (Jena). 2017 Jun;122:107-114. doi: 10.1016/j.zool.2017.04.003. Epub 2017 Apr 26.
Spiders (order Araneae) rely on their silks for essential tasks, such as dispersal, prey capture, and reproduction. Spider silks are largely composed of spidroins, members of a protein family that are synthesized in silk glands. As needed, silk stored in silk glands is extruded through spigots on the spinnerets. Nearly all studies of spider silks have been conducted on females; thus, little is known about male silk biology. To shed light on silk use by males, we compared silk gene expression profiles of mature males to those of females from three cob-web weaving species (Theridiidae). We de novo assembled species-specific male transcriptomes from Latrodectus hesperus, Latrodectus geometricus, and Steatoda grossa followed by differential gene expression analyses. Consistent with their complement of silk spigots, male theridiid spiders express appreciable amounts of aciniform, major ampullate, minor ampullate, and pyriform spidroin genes but not tubuliform spidroin genes. The relative expression levels of particular spidroin genes varied between sexes and species. Because mature males desert their prey-capture webs and become cursorial in their search for mates, we anticipated that major ampullate (dragline) spidroin genes would be the silk genes most highly expressed by males. Indeed, major ampullate spidroin genes had the highest expression in S. grossa males. However, minor ampullate spidroin genes were the most highly expressed spidroin genes in L. geometricus and L. hesperus males. Our expression profiling results suggest species-specific adaptive divergence of silk use by male theridiids.
蜘蛛（蜘蛛目）依靠其蛛丝完成诸如扩散、捕食和繁殖等重要任务。蜘蛛丝主要由蛛丝蛋白组成，蛛丝蛋白是在丝腺中合成的一个蛋白质家族的成员。根据需要，储存在丝腺中的丝会通过纺丝器上的喷丝头挤出。几乎所有关于蜘蛛丝的研究都是针对雌性蜘蛛进行的；因此，对于雄性蜘蛛丝的生物学特性了解甚少。为了阐明雄性蜘蛛对蛛丝的利用情况，我们比较了三种结网蜘蛛（球蛛科）成熟雄性和雌性的蛛丝基因表达谱。我们从西方黑寡妇蜘蛛、间斑寇蛛和肥腹蛛中从头组装了物种特异性的雄性转录组，随后进行了差异基因表达分析。与它们的蛛丝喷丝头组成相匹配，雄性球蛛科蜘蛛表达相当数量的aciniform、major ampullate、minor ampullate和梨形蛛丝蛋白基因，但不表达管状蛛丝蛋白基因。特定蛛丝蛋白基因的相对表达水平在性别和物种之间有所不同。由于成熟雄性会离开它们的捕食网，在寻找配偶时变得善于奔跑，我们预计major ampullate（拖牵丝）蛛丝蛋白基因将是雄性蜘蛛中表达量最高的蛛丝基因。事实上，major ampullate蛛丝蛋白基因在肥腹蛛雄性中表达量最高。然而，minor ampullate蛛丝蛋白基因是间斑寇蛛和西方黑寡妇蜘蛛雄性中表达量最高的蛛丝蛋白基因。我们的表达谱分析结果表明，雄性球蛛科蜘蛛在蛛丝利用方面存在物种特异性的适应性分化。
