Ancient properties of spider silks revealed by the complete gene sequence of the prey-wrapping silk protein (AcSp1).
Ancient properties of spider silks revealed by the complete gene sequence of the prey-wrapping silk protein (AcSp1).
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DOI：
10.1093/molbev/mss254
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发表时间：
2013-03
影响因子：
10.7
通讯作者：
Hayashi CY
中科院分区：
文献类型：
--
作者：
Ayoub NA;Garb JE;Kuelbs A;Hayashi CY
蜘蛛丝纤维具有令人印象深刻的机械性能，主要由一个单一基因家族编码的高度重复的结构蛋白（称为蜘蛛蛋白）组成。大多数蜘蛛基因的特征是不完全已知的，因为它们的极端大小（通常为bbb9 kb）和重复，限制了对产生其不寻常基因结构的进化过程的理解。到目前为止，唯一完整的蜘蛛基因来自西方黑寡妇的拖丝，Latrodectus hesperus。在这里，我们描述了第一个完整的基因序列，编码腺状蜘蛛AcSp1，蜘蛛包裹猎物纤维的主要成分。L. hesperus AcSp1包含一个巨大的外显子（~ 19 kb）。AcSp1重复序列在两个寡妇物种之间（~ 94%的一致性）以及在寡妇和远亲的圆织者之间（~ 30%的一致性）是异常保守的，这与对其氨基酸序列的强纯化选择的历史一致。此外，在黑寡妇AcSp1中发现的16个重复序列（每个长371-375个氨基酸）在核苷酸水平上平均相同bb0 99%。氨基酸序列的稳定选择、沉默位点的选择和基因内重组的结合可能解释了AcSp1重复序列的极端均匀性。此外，对蜘蛛类似性的系统发育分析支持基因复制事件与合成卵丝的腺状腺和管状腺的特化同时发生。我们的L. hesperus AcSp1的重复序列在长度和氨基酸组成上与拖丝蜘蛛有很大的不同，这为开发基于丝的仿生技术扩展了知识库。
Spider silk fibers have impressive mechanical properties and are primarily composed of highly repetitive structural proteins (termed spidroins) encoded by a single gene family. Most characterized spidroin genes are incompletely known because of their extreme size (typically >9 kb) and repetitiveness, limiting understanding of the evolutionary processes that gave rise to their unusual gene architectures. The only complete spidroin genes characterized thus far form the dragline in the Western black widow, Latrodectus hesperus. Here, we describe the first complete gene sequence encoding the aciniform spidroin AcSp1, the primary component of spider prey-wrapping fibers. L. hesperus AcSp1 contains a single enormous (∼19 kb) exon. The AcSp1 repeat sequence is exceptionally conserved between two widow species (∼94% identity) and between widows and distantly related orb-weavers (∼30% identity), consistent with a history of strong purifying selection on its amino acid sequence. Furthermore, the 16 repeats (each 371–375 amino acids long) found in black widow AcSp1 are, on average, >99% identical at the nucleotide level. A combination of stabilizing selection on amino acid sequence, selection on silent sites, and intragenic recombination likely explains the extreme homogenization of AcSp1 repeats. In addition, phylogenetic analyses of spidroin paralogs support a gene duplication event occurring concomitantly with specialization of the aciniform glands and the tubuliform glands, which synthesize egg-case silk. With repeats that are dramatically different in length and amino acid composition from dragline spidroins, our L. hesperus AcSp1 expands the knowledge base for developing silk-based biomimetic technologies.
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影响因子：
3.3
作者：
BREMER, K
通讯作者：
BREMER, K
影响因子：
3.8
作者：
Beckwitt, R;Arcidiacono, S;Stote, R
通讯作者：
Stote, R
影响因子：
4.1
作者：
Ayoub, Nadia A.;Garb, Jessica E.;Hayashi, Cheryl Y.
通讯作者：
Hayashi, Cheryl Y.
影响因子：
3.7
作者：
Agnarsson I;Kuntner M;Blackledge TA
通讯作者：
Blackledge TA
影响因子：
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作者：
Chinali, Alberto;Vater, Wolfram;Weisshart, Klaus
通讯作者：
Weisshart, Klaus