Tissue-specific and glucose-responsive expression of the pancreatic derived factor (PANDER) promoter.
Pancreatic derived factor (PANDER) is a recently identified cytokine-like protein that is dominantly expressed in the islets of Langerhans of the pancreas. To investigate the mechanism of tissue-specific regulation of PANDER, we identified and characterized the promoter region. The transcriptional start site was identified 520 bp upstream of the translational start codon by 5'-RLM-RACE. Computer algorithms identified several islet-associated and glucose-responsive binding motifs that included A and E boxes, hepatocyte nuclear factors 1 and 4, Oct-1, and signal transducer and activator of transcription 3, and 5. Reporter gene analysis revealed cell type-specific PANDER promoter expression in islet and liver-derived cell lines. Levels of PANDER mRNA were directly concordant to the observed cell type-specific PANDER promoter gene expression. The minimal element was mapped to the 5'-UTR and located between +200 and +491 relative to the transcriptional start site and imparted maximal gene expression. In addition, several putative glucose-responsive binding sites were further functionally characterized to reveal critical regulatory elements of PANDER. The PANDER promoter was demonstrated to be glucose-responsive in a dose-dependent manner in murine insulinoma beta-TC3 cells and primary murine islets, but unresponsive in glucagon-secreting alpha-TC3 cells. Our findings revealed that the 5'-UTR of PANDER contains the minimal element for gene expression and imparts both tissue-specificity and glucose-responsiveness. The regulation of PANDER gene expression mimics that of insulin and suggests a potential biological function of PANDER involved in metabolic homeostasis.
Burkhardt
Brant R
BR
Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, 5135 Main, 34th Street and Civic Center Blvd., Philadelphia, PA 19104-4399, USA.
Yang
Michael C
MC
Robert
Claudia E
CE
Greene
Scott R
SR
McFadden
K Kelly
KK
Yang
Jichun
J
Wu
Jianmei
J
Gao
Zhiyong
Z
Wolf
Bryan A
BA
D020121:5' Untranslated Regions; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D016384:Consensus Sequence; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D005947:Glucose / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007340:Insulinoma; D007515:Islets of Langerhans / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D008156:Luciferases / Q000032:analysis / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D010179:Pancreas / Q000737:chemistry* / Q000166:cytology; D010190:Pancreatic Neoplasms; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
D020121:5' Untranslated Regions; D016207:Cytokines; C504749:PANDER protein, mouse; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins; D008156:Luciferases; D005947:Glucose