TY - JOUR
T1 - Similarities and differences in the regulation of N-myc and c-myc genes in murine embryonal carcinoma cells
AU - Sejersen, Thomas
AU - Rahm, Magnus
AU - Szabo, Gabor
AU - Ingvarsson, Sigurdur
AU - Sümegi, Janos
N1 - Funding Information:
We thank Mrs. Ulla Krondahl for excellent technical assistance.S uggestionsa nd commentso n the manuscriptb y Drs. N. R. Ringertz and G. Klein are gratefullya cknowledged.W e are indebtedt o the following colleagues for providing us with cells and cloned genes: Drs. M. Schwab (pNb1) K. B. Marcu (pMc-myc54),M . Buckingham (pAm91), J. R. E. Wells (pCH3,3E), S. M. Tilghman (APFl), B. Ephrrussi (F9), and H. Jakob (PCC7). Financial support was obtainedf rom the Swedish Medical
PY - 1987/10
Y1 - 1987/10
N2 - c-myc and N-myc are closely related genes coding for putative DNA-binding proteins. The protein products of both genes have been implicated in the regulation of growth of normal and neoplastic cells. We compared the regulation of N-myc and c-myc expression under different growth conditions as well as in vitro differentiation of the murine EC lines F9 and PCC7. N-myc and c-myc expression was found to be regulated by distinct mechanisms, although similarities exist. Differences were found both at the transcriptional and at the post-transcriptional level. The two myc genes were regulated by mainly post-transcriptional mechanisms, but in PCC7 cells nuclear run-on assays indicated that c-myc was repressed at the level of transcription. N-myc and c-myc expression was negatively regulated at a post-transcriptional level in F9 and PCC7 cells during differentiation to visceral endoderm and nerve-like tissue, respectively. Serum stimulation of F9 cells for 4 h induced a sevenfold increase in c-myc transcripts but no significant elevation of N-myc transcripts. Mitogenic stimulation with insulin and transferrin also induced a marked elevation of c-myc but not of N-myc mRNA. In addition, the N-myc and c-myc genes differed in F9 cells with respect to (i) the kinetics of expression following induction of differentiation, c-myc undergoing quicker changes than N-myc; (ii) the response to cycloheximide inhibition of protein synthesis, indicating that c-myc but not N-myc is downregulated by a short-lived protein; and (iii) the half-lives of the transcripts, estimated to be approximately 40 min for c-myc and 130 min for N-myc.
AB - c-myc and N-myc are closely related genes coding for putative DNA-binding proteins. The protein products of both genes have been implicated in the regulation of growth of normal and neoplastic cells. We compared the regulation of N-myc and c-myc expression under different growth conditions as well as in vitro differentiation of the murine EC lines F9 and PCC7. N-myc and c-myc expression was found to be regulated by distinct mechanisms, although similarities exist. Differences were found both at the transcriptional and at the post-transcriptional level. The two myc genes were regulated by mainly post-transcriptional mechanisms, but in PCC7 cells nuclear run-on assays indicated that c-myc was repressed at the level of transcription. N-myc and c-myc expression was negatively regulated at a post-transcriptional level in F9 and PCC7 cells during differentiation to visceral endoderm and nerve-like tissue, respectively. Serum stimulation of F9 cells for 4 h induced a sevenfold increase in c-myc transcripts but no significant elevation of N-myc transcripts. Mitogenic stimulation with insulin and transferrin also induced a marked elevation of c-myc but not of N-myc mRNA. In addition, the N-myc and c-myc genes differed in F9 cells with respect to (i) the kinetics of expression following induction of differentiation, c-myc undergoing quicker changes than N-myc; (ii) the response to cycloheximide inhibition of protein synthesis, indicating that c-myc but not N-myc is downregulated by a short-lived protein; and (iii) the half-lives of the transcripts, estimated to be approximately 40 min for c-myc and 130 min for N-myc.
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U2 - 10.1016/0014-4827(87)90389-2
DO - 10.1016/0014-4827(87)90389-2
M3 - Article
C2 - 3308495
AN - SCOPUS:0023567268
SN - 0014-4827
VL - 172
SP - 304
EP - 317
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 2
ER -