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dc.contributor.authorHart, John Een
dc.contributor.authorClarke, Iain Jen
dc.contributor.authorRisbridger, Gail Pen
dc.contributor.authorFerneyhough, Benen
dc.contributor.authorVega-Hernández, Mónicaen
dc.date.accessioned2019-01-18T09:58:58Z
dc.date.available2019-01-18T09:58:58Z
dc.date.issued2018-10-13
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/288224
dc.description.abstractIn the context of a hunt for a postulated hormone that is tissue-mass inhibiting and reproductively associated there is described probable relatedness to a granin protein. A 7-8 kDa polypeptide candidate (gels/MS) appeared in a bioassay-guided fractionation campaign involving sheep plasma. An N-terminal sequence of 14 amino acids was obtained for the polypeptide by Edman degradation. Bioinformatics and molecular biology failed to illuminate any ovine or non-ovine protein which might relate to this sequence. The N-terminal sequence was synthesized as the 14mer peptide EPL001 and surprisingly found to be inhibitory in an assay in vivo of compensatory renal growth in the rat and modulatory of nematode fecundity, in line with the inhibitory hormone hypothesis. Antibodies were raised to EPL001 and their deployment upheld the hypothesis that the EPL001 amino acid sequence is meaningful and relevant, notwithstanding bioinformatic obscurity. Immunohistochemistry (IHC) in sheep, rodents and humans yielded staining of seeming endocrine relevance (e.g. hypothalamus, gonads and neuroendocrine cells in diverse tissues), with apparent upregulation in certain human tumours (e.g. pheochromocytoma). Discrete IHC staining in Drosophila melanogaster embryo brain was seen in glia and in neuroendocrine cells, with staining likely in the corpus cardiacum. The search for the endogenous antigen involved immunoprecipitation (IP) followed by liquid chromatography and mass spectrometry (LC-MS). Feedstocks were PC12 conditioned medium and aqueous extract of rat hypothalamus – both of which had anti-proliferative and pro-apoptotic effects in an assay in vitro involving rat bone marrow cells, which inhibition was subject to prior immunodepletion with an anti-EPL001 antibody – together with fruit fly embryo material. It is concluded that the mammalian antigen is likely secretogranin II (SgII) related. The originally seen 7-8 kDa polypeptide is suggested to be a new proteoform of secretogranin II of ~70 residues, SgII-70, with the anti-EPL001 antibody seeing a discontinuous epitope. The fly antigen is probably Q9W2X8 (UniProt), an uncharacterised protein newly disclosed as a granin 50 and provisionally dubbed macrogranin I (MgI). SgII and Q9W2X8 merit further investigation in the context of tissue-mass inhibition
dc.languageenen
dc.publisherPeerJ Inc.
dc.rightsAttribution 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/*
dc.titleMysterious inhibitory cell regulator investigated and found likely to be secretogranin II relateden
dc.typeArticleen
prism.endingPagee3833
prism.numbere3833en
prism.publicationNamePeerJen
prism.startingPagee3833
prism.volume5en
dc.identifier.doi10.17863/CAM.35538
pubs.declined2019-01-18T09:55:55.522+0000
dcterms.dateAccepted2017-08-30en
rioxxterms.versionofrecord10.7717/peerj.3833en
rioxxterms.versionVoR*
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/en
rioxxterms.licenseref.startdate2017-08-30en
dc.contributor.orcidHart, John E [0000-0003-3195-2664]
dc.contributor.orcidRisbridger, Gail P [0000-0003-3089-4028]
dc.identifier.eissn2167-8359
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idWellcome Trust (096645/Z/11/Z)
cam.issuedOnline2017-10-13en
cam.orpheus.successThu Jan 30 10:53:28 GMT 2020 - The item has an open VoR version.*
rioxxterms.freetoread.startdate2100-01-01


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Attribution 4.0 International
Except where otherwise noted, this item's licence is described as Attribution 4.0 International