Proteomics and deep sequencing comparison of seasonally active venom glands in the platypus reveals novel venom peptides and distinct expression profiles.
The platypus is a venomous monotreme. Male platypuses possess a spur on their hind legs that is connected to glands in the pelvic region. They produce venom only during the breeding season, presumably to fight off conspecifics. We have taken advantage of this unique seasonal production of venom to compare the transcriptomes of in- and out-of-season venom glands, in conjunction with proteomic analysis, to identify previously undiscovered venom genes. Comparison of the venom glands revealed distinct gene expression profiles that are consistent with changes in venom gland morphology and venom volumes in and out of the breeding season. Venom proteins were identified through shot-gun sequenced venom proteomes of three animals using RNA-seq-derived transcripts for peptide-spectral matching. 5,157 genes were expressed in the venom glands, 1,821 genes were up-regulated in the in-season gland, and 10 proteins were identified in the venom. New classes of platypus-venom proteins identified included antimicrobials, amide oxidase, serpin protease inhibitor, proteins associated with the mammalian stress response pathway, cytokines, and other immune molecules. Five putative toxins have only been identified in platypus venom: growth differentiation factor 15, nucleobindin-2, CD55, a CXC-chemokine, and corticotropin-releasing factor-binding protein. These novel venom proteins have potential biomedical and therapeutic applications and provide insights into venom evolution.
Faculty of Veterinary Science, The University of Sydney, Camperdown, NSW 2006, Australia. emily.wong@uq.edu.au
Emily S W
ES
Wong
David
D
Morgenstern
Ehtesham
E
Mofiz
Sara
S
Gombert
Katrina M
KM
Morris
Peter
P
Temple-Smith
Marilyn B
MB
Renfree
Camilla M
CM
Whittington
Glenn F
GF
King
Wesley C
WC
Warren
Anthony T
AT
Papenfuss
Katherine
K
Belov
D000825:Animal Structures / Q000378:metabolism*; D000818:Animals; D020869:Gene Expression Profiling; D059014:High-Throughput Nucleotide Sequencing; D008297:Male; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D010987:Platypus / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012621:Seasons; D014688:Venoms / Q000235:genetics / Q000378:metabolism*
D010455:Peptides; D011506:Proteins; D012333:RNA, Messenger; D014688:Venoms