A single regulatory module of the carbamoylphosphate synthetase I gene executes its hepatic program of expression.
A 469-base pair (bp) upstream regulatory fragment (URF) and the proximal promoter of the carbamoylphosphate synthetase I (CPS) gene were analyzed for their role in the regulation of spatial, developmental, and hormone-induced expression in vivo. The URF is essential and sufficient for hepatocyte-specific expression, periportal localization, perinatal activation and induction by glucocorticoids, and cAMP in transgenic mice. Before birth, the transgene is silent but can be induced by cAMP and glucocorticoids, indicating that these compounds are responsible for the activation of expression at birth. A 102-bp glucocorticoid response unit within the URF, containing binding sites for HNF3, C/EBP, and the glucocorticoid receptor, is the main determinant of the hepatocyte-specific and hormone-controlled activity. Additional sequences are required for a productive interaction between this minimal response unit and the core CPS promoter. These results show that the 469-bp URF, and probably only the 102-bp glucocorticoid response unit, functions as a regulatory module, in that it autonomously executes a correct spatial, developmental and hormonal program of CPS expression in the liver.
Christoffels
V M
VM
Department of Anatomy and Embryology and the Genetically Modified Mice Facility, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
Habets
P E
PE
Das
A T
AT
Clout
D E
DE
van Roon
M A
MA
Moorman
A F
AF
Lamers
W H
WH
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002222:Carbamoyl-Phosphate Synthase (Ammonia) / Q000235:genetics*; D006224:Cricetinae; D017931:DNA Primers; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D008099:Liver / Q000201:enzymology*; D051379:Mice; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D002222:Carbamoyl-Phosphate Synthase (Ammonia)