title: Potential roles of large mafs in cell lineages and developing pancreas.
abstract: OBJECTIVE
  Maf is a family of transcription factor proteins characterized by a typical bZip structure, and mafA, a member of the large-maf family, is a strong transactivator of insulin in cell lines. The present study investigated the expression profiles of the large-maf family proteins in porcine pancreatic tissue and in primary culture cells.
  
  
  METHODS
  Immunohistochemical staining was performed to localize each maf protein. Messenger RNA expression was quantitated by real-time polymerase chain reaction, and protein expression was assessed by Western blotting.
  
  
  RESULTS
  Islet formation was not as clear in newborn pancreatic tissue as in adult pancreatic tissue. MafA- and c-maf-positive cells were more diffusely localized in pancreatic tissue with fewer mafB-positive cell clusters scattered throughout. By contrast, islet formation was clearer, and positive staining for mafA and c-maf tended to be more prominent in the islets of adult pancreatic tissue. Messenger RNA and protein expressions were consistent with the immunohistochemical findings. MafA, mafB, and c-maf coexpressed with insulin-positive cells, and c-maf coexpressed with glucagon-positive cells in adult porcine pancreas based on the results of a double-staining study.
  
  
  CONCLUSIONS
  Large mafs were identified in normal porcine and human pancreas, and the expression levels and localizations of the large mafs in newborn and adult pancreatic tissues differed. Mafs may play important roles in establishing endocrine function during pancreatic cell differentiation.
authors: Institute of Geriatrics, Aoyama Hospital, Tokyo Women's Medical University, Tokyo, Japan.
authors: Mariko
authors: M
authors: Tsuchiya
authors: Shigeki
authors: S
authors: Taniguchi
authors: Kazuki
authors: K
authors: Yasuda
authors: Kosaku
authors: K
authors: Nitta
authors: Atsushi
authors: A
authors: Maeda
authors: Mutsuo
authors: M
authors: Shigemoto
authors: Ken
authors: K
authors: Tsuchiya