Modulation of cholecystokinin (CCK) gene-expression in a human neuroblastoma cell line: effects of serum on enhanced CCK and c-fos mRNA expression.
The effect of fetal-calf serum (FCS) and Forskolin (FKN) on cholecystokinin (CCK) and proto-oncogene c-fos mRNA expression in the human neuroblastoma cell line SK-N-MC, cultured in serum free medium was studied by Northern blot analysis and nuclear run-off transcription analysis. Addition of FCS or FKN gradually increased the basal CCK mRNA level approximately four to six-fold after 2-4 h. In contrast, a strong and transient increase of the c-fos mRNA-level was observed, approximately forty to fifty-fold after 50-60 min over unstimulated cells. Nuclear run-off transcription analysis indicates that c-fos mRNA is constitutively expressed and transcription may be further stimulated by FCS and FKN. Moreover, in SK-N-MC nuclei, transcription of the c-fos gene clearly precedes stimulated CCK-mRNA expression. This suggests that FOS, which is known to form a AP-1 heterodimer transcription complex with the proto-oncogen product, Jun, may bind to the tentative AP-1 binding site, found within the human CCK promoter and thereby modulates basal and enhanced CCK-mRNA expression in SK-N-MC cells.
Department of Clinical Biochemistry (KK 3013), State University Hospital (Rigshospitalet), Copenhagen, Denmark.
H J
HJ
Monstein
K
K
Pedersen
P M
PM
Haahr
D001483:Base Sequence; D015152:Blotting, Northern; D002766:Cholecystokinin / Q000096:biosynthesis* / Q000235:genetics; D003001:Cloning, Molecular; D005576:Colforsin / Q000494:pharmacology; D015342:DNA Probes; D005786:Gene Expression Regulation; D005801:Genes, Homeobox; D016762:Genes, fos; D006801:Humans; D008969:Molecular Sequence Data; D009423:Nervous System Neoplasms / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D000090063:Proto-Oncogene Mas; D015347:RNA Probes; D016372:RNA, Antisense / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D015342:DNA Probes; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D015347:RNA Probes; D016372:RNA, Antisense; D012333:RNA, Messenger; D005576:Colforsin; D002766:Cholecystokinin