Expression, intracellular localization, and gene transcription regulation of the secretory protein 7B2 in endocrine pancreatic cell lines and human insulinomas.
7B2 is a 23-kDa protein encoded by a single gene that is expressed in a variety of neuroendocrine tissues. Although its physiological role has not yet been elucidated, its presence in secretory granules suggests a function in the secretory machinery of certain neuronal and endocrine cells in various species. The present study characterizes the expression of 7B2 in endocrine pancreatic cells. We demonstrate that: (i) 7B2 is highly expressed in human insulinomas; (ii) its ultrastructural localization, associated with secretory granules of A and B cells of the islets, suggests a participation of 7B2 in the secretion of insulin and glucagon; (iii) sequences located in the first intron of the 7B2 gene are required for its transcription in either insulinoma or glucagonoma cell lines; and (iv) in a B cell-like insulinoma cell line, the transcription of 7B2 is regulated by protein kinase A and protein kinase C activators, while in an A-like insulinoma cell line, 7B2 gene transcription seems to be constitutively activated.
Gherzi
R
R
Department of Internal Medicine, Philipps University of Marburg, Germany.
Fehmann
H C
HC
Eissele
R
R
Göke
B
B
D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis*; D015152:Blotting, Northern; D006224:Cricetinae; D015870:Gene Expression; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D005935:Glucagonoma / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007340:Insulinoma / Q000378:metabolism* / Q000473:pathology; D007515:Islets of Langerhans / Q000378:metabolism* / Q000473:pathology; D009419:Nerve Tissue Proteins; D051859:Neuroendocrine Secretory Protein 7B2; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D010907:Pituitary Hormones / Q000032:analysis / Q000096:biosynthesis*; D011061:Poly A / Q000096:biosynthesis / Q000302:isolation & purification; D011401:Promoter Regions, Genetic; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D012333:RNA, Messenger; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D009419:Nerve Tissue Proteins; D051859:Neuroendocrine Secretory Protein 7B2; D010907:Pituitary Hormones; D012333:RNA, Messenger; C497678:SCG5 protein, human; D011061:Poly A; D012313:RNA