title: Two distinct populations of tumor necrosis factor-stimulated gene-6 protein in the extracellular matrix of expanded mouse cumulus cell-oocyte complexes.
abstract: After the luteinizing hormone surge, the cumulus cell-oocyte complexes (COCs) in the preovulatory follicles produce a viscoelastic extracellular matrix, a process that requires the synthesis of hyaluronan as well as the incorporation of some components of the inter-alpha-trypsin inhibitor (IalphaI) family. In this study we report, that a hyaluronan-binding protein, the translated product of tumor necrosis factor-stimulated gene-6 (TSG-6), is also specifically accumulated in this matrix. TSG-6 mRNA expression is quickly upregulated and peaks at approximately 1500 copies/cell 4 h after the ovulatory stimuli as assessed by quantitative reverse transcription-polymerase chain reaction. Immunohistochemistry reveals the colocalization of the TSG-6 protein and hyaluronan around the cumulus and granulosa cells. The TSG-6 protein exists in two distinct populations in the COC matrix as demonstrated by Western-blot analysis. One population is a monomer that is anchored to the matrix by a noncovalent interaction. The second population is a covalent complex with either of the heavy chains of IalphaI and is bound to hyaluronan through a strong interaction that is resistant to denaturing conditions. The specific incorporation of the TSG-6 protein into the COC matrix suggests a structural role for this molecule.
authors.affiliation: Department of Biomedical Engineering, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
authors.forename: D
authors.initials: D
authors.lastname: Mukhopadhyay
authors.forename: V C
authors.initials: VC
authors.lastname: Hascall
authors.forename: A J
authors.initials: AJ
authors.lastname: Day
authors.forename: A
authors.initials: A
authors.lastname: Salustri
authors.forename: C
authors.initials: C
authors.lastname: Fülöp
mesh_terms: D000510:Alpha-Globulins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002478:Cells, Cultured; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D005498:Follicular Phase; D006820:Hyaluronic Acid / Q000378:metabolism; D007150:Immunohistochemistry; D046911:Macromolecular Substances; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009865:Oocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006080:Ovarian Follicle / Q000166:cytology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020539:Sequence Analysis, Protein; D015854:Up-Regulation
chemical_list: D000510:Alpha-Globulins; D015815:Cell Adhesion Molecules; D046911:Macromolecular Substances; D012333:RNA, Messenger; C513057:Tnfaip6 protein, mouse; C011877:inter-alpha-inhibitor; D006820:Hyaluronic Acid