Expression of c-raf-1 and A-raf-1 during differentiation of 3T3-L1 preadipocyte fibroblasts into adipocytes.
The objective of this study was to examine the expression of the c-raf-1 and A-rat-1 protooncogenes during differentiation of 3T3-L1 preadipocytes into adipocytes. At confluence, prior to initiation of differentiation c-raf and A-raf steady state mRNA levels were low. Expression of c-raf and A-raf began to increase 72 hours following initiation of differentiation by treatment with differentiation medium, reaching a maximum increase of 3 to 6-fold and 3 to 4-fold respectively by 190 hours. The increase of c-raf and A-raf steady state message levels occurred concomitant with the onset of differentiation as indicated by increased levels of glycerol-3-phosphate dehydrogenase mRNA. These changes were compared with those for several other protooncogene mRNAs including c-myc, c-fos, H-ras and histone H3. These results are the first to show increase expression of the raf protooncogenes during terminal differentiation rather than in association with proliferation.
Zmuidzinas
A
A
Department of Biochemistry, Dartmouth Medical School Hanover, NH 03756.
Gould
G W
GW
Yager
J D
JD
D000199:Actins / Q000235:genetics; D000273:Adipose Tissue / Q000166:cytology / Q000502:physiology*; D000818:Animals; D015152:Blotting, Northern; D002454:Cell Differentiation; D005786:Gene Expression Regulation; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics; D006657:Histones / Q000235:genetics; D051379:Mice; D009004:Monosaccharide Transport Proteins / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019908:Proto-Oncogene Proteins c-raf; D012333:RNA, Messenger / Q000235:genetics
D000199:Actins; D006657:Histones; D009004:Monosaccharide Transport Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D005954:Glucosephosphate Dehydrogenase; D019908:Proto-Oncogene Proteins c-raf