Department of Biology, Washington and Lee University, Lexington, VA, 24450, USA.
Department of Biology, University of California, Riverside, CA, 92521, USA.
Sci Rep. 2017 Aug 21;7(1):8393. doi: 10.1038/s41598-017-07388-1.
Spider silk synthesis is an emerging model for the evolution of tissue-specific gene expression and the role of gene duplication in functional novelty, but its potential has not been fully realized. Accordingly, we quantified transcript (mRNA) abundance in seven silk gland types and three non-silk gland tissues for three cobweb-weaving spider species. Evolutionary analyses based on expression levels of thousands of homologous transcripts and phylogenetic reconstruction of 605 gene families demonstrated conservation of expression for each gland type among species. Despite serial homology of all silk glands, the expression profiles of the glue-forming aggregate glands were divergent from fiber-forming glands. Also surprising was our finding that shifts in gene expression among silk gland types were not necessarily coupled with gene duplication, even though silk-specific genes belong to multi-paralog gene families. Our results challenge widely accepted models of tissue specialization and significantly advance efforts to replicate silk-based high-performance biomaterials.
蜘蛛丝合成是组织特异性基因表达进化和基因复制在功能新颖性中的作用的新兴模型，但它的潜力尚未得到充分实现。因此，我们对三种蛛网蜘蛛的七种丝腺类型和三种非丝腺组织中的转录本（mRNA）丰度进行了定量分析。基于数千个同源转录本的表达水平的进化分析和 605 个基因家族的系统发育重建表明，每种腺体类型在物种间的表达都是保守的。尽管所有丝腺都具有序列同源性，但胶状聚合腺的表达谱与纤维形成腺不同。另一个令人惊讶的发现是，丝腺类型之间的基因表达变化不一定与基因复制相关，尽管丝腺特异性基因属于多基因家族。我们的研究结果对组织特化的广泛接受的模型提出了挑战，并极大地推动了复制基于丝的高性能生物材料的努力。
