Expression of the phosphoenolpyruvate carboxykinase gene in 3T3-F442A adipose cells: effects of retinoic acid and differentiation.
3T3-F442A adipocytes express the gene encoding cytosolic phosphoenolpyruvate carboxykinase (GTP) (PEPCK). Retinoic acid (RA) caused a 5-fold induction of PEPCK mRNA within 6 h in these cells with a half-maximal effective concentration of approximately 75 microM. This effect was independent of cycloheximide and inhibited by actinomycin D. In vitro run-on experiments using isolated nuclei confirmed that the RA-induced increase was mainly due to an increased rate of transcription of the gene. Stable transfectants bearing either the region of the PEPCK promoter from -2100 to +69 fused to the chloramphenicol acetyltransferase (CAT) gene (pPL1-CAT) or -600 to +69 fused to CAT (pPL9-CAT) were used to study PEPCK gene regulation during differentiation. The same transfected cells were used to analyse the RA effect. Preadipocytes containing pPL1-CAT expressed a much lower level of CAT activity than did adipocytes. pPL9-CAT was not expressed in either preadipocytes or adipocytes. RA induced the expression of CAT activity in preadipocytes and adipocytes transfected with pPL1-CAT, but had no effect in cells transfected with pPL9-CAT. These results suggest that one or more DNA sequences located between -2100 and -600 bp of the PEPCK promoter is required for adipocyte-specific expression of this gene. RA action is independent of the state of differentiation and appears to require different elements in fat cells from those required in liver.
Antras-Ferry
J
J
Centre de Recherche sur l'Endocrinologie Moléculaire et le Développement, C.N.R.S., Meudon, France.
Franckhauser
S
S
Robin
D
D
Robin
P
P
Granner
D K
DK
Forest
C
C
D016475:3T3 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004790:Enzyme Induction; D051379:Mice; D008969:Molecular Sequence Data; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology*
D012333:RNA, Messenger; D003609:Dactinomycin; D014212:Tretinoin; D003513:Cycloheximide; D010729:Phosphoenolpyruvate Carboxykinase (GTP)