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Title: Unveiling the topmost layers of spider silks by ultra-high resolution mapping of sections
Abstract
While spider silk threads mainly consist of a core of partially crystalline silk proteins, it has been found that they also exhibit a very thin skin layer of distinctMore>>
Creator(s):
; ; ; ; ; ; ;
Publisher:
European Synchrotron Radiation Facility
Publication Year:
NSF-PAR ID:
10383120
Subject(s):
Life Sciences LS-3087 ID13
Award ID(s):
1905902 2105158
Sponsoring Org:
National Science Foundation
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  3. Abstract Background

    Spiders have evolved two types of sticky capture threads: one with wet adhesive spun by ecribellate orb-weavers and another with dry adhesive spun by cribellate spiders. The evolutionary history of cribellate capture threads is especially poorly understood. Here, we use genomic approaches to catalog the spider-specific silk gene family (spidroins) for the cribellate orb-weaverUloborus diversus.

    Results

    We show that the cribellar spidroin, which forms the puffy fibrils of cribellate threads, has three distinct repeat units, one of which is conserved across cribellate taxa separated by ~ 250 Mya. We also propose candidates for a new silk type, paracribellar spidroins, which connect the puffy fibrils to pseudoflagelliform support lines. Moreover, we describe the complete repeat architecture for the pseudoflagelliform spidroin (Pflag), which contributes to extensibility of pseudoflagelliform axial fibers.

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    Our finding that Pflag is closely related to Flag, supports homology of the support lines of cribellate and ecribellate capture threads. It further suggests an evolutionary phase following gene duplication, in which both Flag and Pflag were incorporated into the axial lines, with subsequent loss of Flag in uloborids, and increase in expression of Flag in ecribellate orb-weavers, explaining the distinct mechanical properties of the axial lines of these two groups.

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