Expression of c-fos antisense RNA inhibits the differentiation of F9 cells to parietal endoderm.
To test the putative role of c-fos in F9 differentiation, we have attempted to inhibit c-fos expression in these cells using an SV40-based expression vector (pSVneo-sof) that programs expression of c-fos antisense (sof) sequences as a 3' extension of a neo mRNA transcript. Of six G418-resistant clones isolated in transfection experiments, five expressed neo-sof transcripts. Two clones synthesized polyadenylated mRNA of the expected size (3.8 kb), two were smaller than expected, and one was larger. Two clones that expressed reduced levels of c-fos protein were inhibited in the induction of laminin, type IV collagen, and proteoglycan-19 RNA transcripts measured after 4 days of differentiation induction with RA and dibutyryl cyclic AMP. Also inhibited was the induction of the differentiation markers, TROMA-1 and TROMA-3. Antisense-expressing cells were not inhibited in the differentiation pathway to visceral endoderm since the alpha-fetoprotein gene was activated normally. We conclude that c-fos antisense expression inhibits some aspects of differentiation in F9 cells.
Edwards
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Cancer Research Center, La Jolla Cancer Research Foundation, California 92037.
Rundell
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Adamson
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D003994:Bucladesine / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D003094:Collagen / Q000235:genetics; D004274:DNA, Recombinant; D004707:Endoderm / Q000473:pathology*; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D007124:Immunoenzyme Techniques; D007797:Laminin / Q000235:genetics; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D011509:Proteoglycans / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos; D012313:RNA / Q000235:genetics*; D016372:RNA, Antisense; D012333:RNA, Messenger / Q000235:genetics; D013539:Simian virus 40 / Q000235:genetics; D013724:Teratoma / Q000473:pathology*; D014158:Transcription, Genetic; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D004274:DNA, Recombinant; D007797:Laminin; D011509:Proteoglycans; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016372:RNA, Antisense; D012333:RNA, Messenger; D014212:Tretinoin; D012313:RNA; D003994:Bucladesine; D003094:Collagen