Complex gene expression in the dragline silk producing glands of the Western black widow (Latrodectus hesperus)

Amanda K. Lane; Cheryl Y. Hayashi; Gregg B. Whitworth; Nadia A. Ayoub

doi:10.1186/1471-2164-14-846

Complex gene expression in the dragline silk producing glands of the Western black widow (Latrodectus hesperus)

Amanda K. Lane, Cheryl Y. Hayashi, Gregg B. Whitworth, Nadia A. Ayoub

Research output: Contribution to journal › Article › peer-review

24 Scopus citations

Abstract

Background: Orb-web and cob-web weaving spiders spin dragline silk fibers that are among the strongest materials known. Draglines are primarily composed of MaSp1 and MaSp2, two spidroins (spider fibrous proteins) expressed in the major ampullate (MA) silk glands. Prior genetic studies of dragline silk have focused mostly on determining the sequence of these spidroins, leaving other genetic aspects of silk synthesis largely uncharacterized. Results: Here, we used deep sequencing to profile gene expression patterns in the Western black widow, Latrodectus hesperus. We sequenced millions of 3′-anchored " tags" of cDNAs derived either from MA glands or control tissue (cephalothorax) mRNAs, then associated the tags with genes by compiling a reference database from our newly constructed normalized L. hesperus cDNA library and published L. hesperus sequences. We were able to determine transcript abundance and alternative polyadenylation of each of three loci encoding MaSp1. The ratio of MaSp1:MaSp2 transcripts varied between individuals, but on average was similar to the estimated ratio of MaSp1:MaSp2 in dragline fibers. We also identified transcription of TuSp1 in MA glands, another spidroin family member that encodes the primary component of egg-sac silk, synthesized in tubuliform glands. In addition to the spidroin paralogs, we identified 30 genes that are more abundantly represented in MA glands than cephalothoraxes and represent new candidates for involvement in spider silk synthesis. Conclusions: Modulating expression rates of MaSp1 variants as well as MaSp2 and TuSp1 could lead to differences in mechanical properties of dragline fibers. Many of the newly identified candidate genes likely encode secreted proteins, suggesting they could be incorporated into dragline fibers or assist in protein processing and fiber assembly. Our results demonstrate previously unrecognized transcript complexity in spider silk glands.

Original language	English (US)
Article number	846
Journal	BMC Genomics
Volume	14
Issue number	1
DOIs	https://doi.org/10.1186/1471-2164-14-846
State	Published - Dec 2 2013
Externally published	Yes

Bibliographical note

Funding Information:
We thank K. Bezold, Washington and Lee University’s BIOL 221 Winter 2010 class, and E. Brassfield for their help collecting sequence data. T. Girke and T. Backman contributed tag-processing scripts. J. Satterly assisted in reference formatting. T. Clarke, D. Ireland, J. Satterly, and D. Todd provided helpful comments on the manuscript. This work was supported by the National Science Foundation (IOS-0951886 to NAA, IOS-0951061 to CYH), National Institutes of Health (F32 GM78875-1A to NAA), Army Research Office (W911NF-06-1-0455 to CYH), and Washington and Lee University through Lenfest Summer Fellowships to NAA and GBW.

Keywords

Alternative polyadenylation
MaSp1
Major ampullate glands
Spider
Spidroin
Tag profiling

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title = "Complex gene expression in the dragline silk producing glands of the Western black widow (Latrodectus hesperus)",

abstract = "Background: Orb-web and cob-web weaving spiders spin dragline silk fibers that are among the strongest materials known. Draglines are primarily composed of MaSp1 and MaSp2, two spidroins (spider fibrous proteins) expressed in the major ampullate (MA) silk glands. Prior genetic studies of dragline silk have focused mostly on determining the sequence of these spidroins, leaving other genetic aspects of silk synthesis largely uncharacterized. Results: Here, we used deep sequencing to profile gene expression patterns in the Western black widow, Latrodectus hesperus. We sequenced millions of 3′-anchored {"} tags{"} of cDNAs derived either from MA glands or control tissue (cephalothorax) mRNAs, then associated the tags with genes by compiling a reference database from our newly constructed normalized L. hesperus cDNA library and published L. hesperus sequences. We were able to determine transcript abundance and alternative polyadenylation of each of three loci encoding MaSp1. The ratio of MaSp1:MaSp2 transcripts varied between individuals, but on average was similar to the estimated ratio of MaSp1:MaSp2 in dragline fibers. We also identified transcription of TuSp1 in MA glands, another spidroin family member that encodes the primary component of egg-sac silk, synthesized in tubuliform glands. In addition to the spidroin paralogs, we identified 30 genes that are more abundantly represented in MA glands than cephalothoraxes and represent new candidates for involvement in spider silk synthesis. Conclusions: Modulating expression rates of MaSp1 variants as well as MaSp2 and TuSp1 could lead to differences in mechanical properties of dragline fibers. Many of the newly identified candidate genes likely encode secreted proteins, suggesting they could be incorporated into dragline fibers or assist in protein processing and fiber assembly. Our results demonstrate previously unrecognized transcript complexity in spider silk glands.",

keywords = "Alternative polyadenylation, MaSp1, Major ampullate glands, Spider, Spidroin, Tag profiling",

author = "Lane, {Amanda K.} and Hayashi, {Cheryl Y.} and Whitworth, {Gregg B.} and Ayoub, {Nadia A.}",

note = "Funding Information: We thank K. Bezold, Washington and Lee University{\textquoteright}s BIOL 221 Winter 2010 class, and E. Brassfield for their help collecting sequence data. T. Girke and T. Backman contributed tag-processing scripts. J. Satterly assisted in reference formatting. T. Clarke, D. Ireland, J. Satterly, and D. Todd provided helpful comments on the manuscript. This work was supported by the National Science Foundation (IOS-0951886 to NAA, IOS-0951061 to CYH), National Institutes of Health (F32 GM78875-1A to NAA), Army Research Office (W911NF-06-1-0455 to CYH), and Washington and Lee University through Lenfest Summer Fellowships to NAA and GBW.",

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doi = "10.1186/1471-2164-14-846",

language = "English (US)",

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T1 - Complex gene expression in the dragline silk producing glands of the Western black widow (Latrodectus hesperus)

AU - Lane, Amanda K.

AU - Hayashi, Cheryl Y.

AU - Whitworth, Gregg B.

AU - Ayoub, Nadia A.

N1 - Funding Information: We thank K. Bezold, Washington and Lee University’s BIOL 221 Winter 2010 class, and E. Brassfield for their help collecting sequence data. T. Girke and T. Backman contributed tag-processing scripts. J. Satterly assisted in reference formatting. T. Clarke, D. Ireland, J. Satterly, and D. Todd provided helpful comments on the manuscript. This work was supported by the National Science Foundation (IOS-0951886 to NAA, IOS-0951061 to CYH), National Institutes of Health (F32 GM78875-1A to NAA), Army Research Office (W911NF-06-1-0455 to CYH), and Washington and Lee University through Lenfest Summer Fellowships to NAA and GBW.

PY - 2013/12/2

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N2 - Background: Orb-web and cob-web weaving spiders spin dragline silk fibers that are among the strongest materials known. Draglines are primarily composed of MaSp1 and MaSp2, two spidroins (spider fibrous proteins) expressed in the major ampullate (MA) silk glands. Prior genetic studies of dragline silk have focused mostly on determining the sequence of these spidroins, leaving other genetic aspects of silk synthesis largely uncharacterized. Results: Here, we used deep sequencing to profile gene expression patterns in the Western black widow, Latrodectus hesperus. We sequenced millions of 3′-anchored " tags" of cDNAs derived either from MA glands or control tissue (cephalothorax) mRNAs, then associated the tags with genes by compiling a reference database from our newly constructed normalized L. hesperus cDNA library and published L. hesperus sequences. We were able to determine transcript abundance and alternative polyadenylation of each of three loci encoding MaSp1. The ratio of MaSp1:MaSp2 transcripts varied between individuals, but on average was similar to the estimated ratio of MaSp1:MaSp2 in dragline fibers. We also identified transcription of TuSp1 in MA glands, another spidroin family member that encodes the primary component of egg-sac silk, synthesized in tubuliform glands. In addition to the spidroin paralogs, we identified 30 genes that are more abundantly represented in MA glands than cephalothoraxes and represent new candidates for involvement in spider silk synthesis. Conclusions: Modulating expression rates of MaSp1 variants as well as MaSp2 and TuSp1 could lead to differences in mechanical properties of dragline fibers. Many of the newly identified candidate genes likely encode secreted proteins, suggesting they could be incorporated into dragline fibers or assist in protein processing and fiber assembly. Our results demonstrate previously unrecognized transcript complexity in spider silk glands.

AB - Background: Orb-web and cob-web weaving spiders spin dragline silk fibers that are among the strongest materials known. Draglines are primarily composed of MaSp1 and MaSp2, two spidroins (spider fibrous proteins) expressed in the major ampullate (MA) silk glands. Prior genetic studies of dragline silk have focused mostly on determining the sequence of these spidroins, leaving other genetic aspects of silk synthesis largely uncharacterized. Results: Here, we used deep sequencing to profile gene expression patterns in the Western black widow, Latrodectus hesperus. We sequenced millions of 3′-anchored " tags" of cDNAs derived either from MA glands or control tissue (cephalothorax) mRNAs, then associated the tags with genes by compiling a reference database from our newly constructed normalized L. hesperus cDNA library and published L. hesperus sequences. We were able to determine transcript abundance and alternative polyadenylation of each of three loci encoding MaSp1. The ratio of MaSp1:MaSp2 transcripts varied between individuals, but on average was similar to the estimated ratio of MaSp1:MaSp2 in dragline fibers. We also identified transcription of TuSp1 in MA glands, another spidroin family member that encodes the primary component of egg-sac silk, synthesized in tubuliform glands. In addition to the spidroin paralogs, we identified 30 genes that are more abundantly represented in MA glands than cephalothoraxes and represent new candidates for involvement in spider silk synthesis. Conclusions: Modulating expression rates of MaSp1 variants as well as MaSp2 and TuSp1 could lead to differences in mechanical properties of dragline fibers. Many of the newly identified candidate genes likely encode secreted proteins, suggesting they could be incorporated into dragline fibers or assist in protein processing and fiber assembly. Our results demonstrate previously unrecognized transcript complexity in spider silk glands.

KW - Alternative polyadenylation

KW - MaSp1

KW - Major ampullate glands

KW - Spider

KW - Spidroin

KW - Tag profiling

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Complex gene expression in the dragline silk producing glands of the Western black widow (Latrodectus hesperus)

Abstract

Bibliographical note

Keywords

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