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- Title
Characterization of the mouse islet-specific glucose-6-phosphatase catalytic subunit-related protein gene promoter by in situ footprinting: correlation with fusion gene expression in the islet-derived betaTC-3 and hamster insulinoma tumor cell lines.
- Authors
Bischof, Larry J.; Martin, Cyrus C.; Svitek, Christina A.; Stadelmaier, Beth T.; Hornbuckle, Lauri A.; Goldman, Joshua K.; Oeser, James K.; Hutton, John C.; O'Brien, Richard M.; Bischof, L J; Martin, C C; Svitek, C A; Stadelmaier, B T; Hornbuckle, L A; Goldman, J K; Oeser, J K; Hutton, J C; O'Brien, R M
- Abstract
Glucose-6-phosphatase (G6Pase) is a multicomponent system located in the endoplasmic reticulum comprising a catalytic subunit and transporters for glucose-6-phosphate, inorganic phosphate, and glucose. We have recently cloned a novel gene that encodes an islet-specific G6Pase catalytic subunit-related protein (IGRP) (Ebert et al., Diabetes 48:543-551, 1999). To begin to investigate the molecular basis for the islet-specific expression of the IGRP gene, a series of truncated IGRP-chloramphenicol acetyltransferase (CAT) fusion genes were transiently transfected into the islet-derived mouse betaTC-3 and hamster insulinoma tumor cell lines. In both cell lines, basal fusion gene expression decreased upon progressive deletion of the IGRP promoter sequence between -306 and -66, indicating that multiple promoter regions are required for maximal IGRP-CAT expression. The ligation-mediated polymerase chain reaction footprinting technique was then used to compare trans-acting factor binding to the IGRP promoter in situ in betaTC-3 cells, which express the endogenous IGRP gene, and adrenocortical Y1 cells, which do not. Multiple trans-acting factor binding sites were selectively identified in betaTC-3 cells that correlate with regions of the IGRP promoter identified as being required for basal IGRP-CAT fusion gene expression. The data suggest that hepatocyte nuclear factor 3 may be important for basal IGRP gene expression, as it is for glucagon, GLUT2, and Pdx-1 gene expression. In addition, binding sites for several trans-acting factors not previously associated with islet gene expression, as well as binding sites for potentially novel proteins, were identified.
- Subjects
GENE expression; PROTEINS; ANIMAL experimentation; CELL lines; CHEMISTRY; COMPARATIVE studies; DOCUMENTATION; GENES; GENETIC techniques; HAMSTERS; ISLANDS of Langerhans; ISLANDS of Langerhans tumors; RESEARCH methodology; MEDICAL cooperation; MICE; NUCLEOTIDES; PAPER chromatography; PEPTIDES; PHOSPHATASES; RESEARCH; TRANSCRIPTION factors; TRANSFERASES; DNA-binding proteins; EVALUATION research; NUCLEAR proteins; PHYSIOLOGY
- Publication
Diabetes, 2001, Vol 50, Issue 3, p502
- ISSN
0012-1797
- Publication type
journal article
- DOI
10.2337/diabetes.50.3.502