Induction of nerve growth factor-induced gene-B (NGFI-B) as an early event in the cyclic adenosine monophosphate response of dog thyrocytes in primary culture.
We investigated the induction of nerve growth factor-induced gene-B (NGFI-B) in dog thyrocytes in primary culture stimulated by different agents. The dog NGFI-B complementary DNA (cDNA) was cloned from a cDNA library of dog thyrocytes and used to study, by Northern blotting, the level of NGFI-B messenger RNA (mRNA) in those cells. We have shown that TSH and forskolin, which both induce proliferation and differentiation of the thyroid cells by activation of the protein kinase A pathway, lead to a strong and transient expression of two NGFI-B mRNA species, which differ in the length of the poly(A) tail. In contrast, 12-O-tetradecanoyl-13-phorbol-acetate (TPA) and epidermal growth factor, which induce proliferation and dedifferentiation of those cells by activation of the protein kinase C and the protein tyrosine kinase cascade, respectively, lead to a weaker expression of NGFI-B mRNA. In parallel, we studied the transactivation capacity of NGFI-B in the same cell system by transient transfection of a chloramphenicol acetyl transferase reporter construction containing a NGFI-B-dependent synthetic promoter. The highest transactivation was observed after forskolin stimulation, whereas transactivation after TPA stimulation was weak and no significant transactivation was observed after epidermal growth factor stimulation. Taken together, these results show that NGFI-B is an immediate early gene product that is mainly induced by the cAMP-dependent pathway in dog thyrocytes. Moreover they suggest that NGFI-B expression could be one of the early transcriptional changes induced specifically by this cascade and leading to differentiation and/or proliferation of these cells.
Institut de Recherche Interdisciplinaire en Biologie Humaine et Nucléaire, Faculté de Médecine, Université Libra de Bruxelles, Belgique.
B
B
Pichon
C
C
Jimenez-Cervantes
I
I
Pirson
C
C
Maenhaut
D
D
Christophe
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D017124:Conserved Sequence; D000242:Cyclic AMP / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry; D004285:Dogs; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D015723:Gene Library; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D017386:Sequence Homology, Amino Acid; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology; D014157:Transcription Factors / Q000096:biosynthesis* / Q000737:chemistry; D014158:Transcription, Genetic / Q000187:drug effects; D014981:Xenopus
D004268:DNA-Binding Proteins; C539821:NR4A1 protein, human; C539818:Nr4a1 protein, mouse; C539820:Nr4a1 protein, rat; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D014157:Transcription Factors; D005576:Colforsin; D004815:Epidermal Growth Factor; D013972:Thyrotropin; D000242:Cyclic AMP; D013755:Tetradecanoylphorbol Acetate