title: Effect of 5'-methylthioadenosine on RNA and DNA synthesis in cultured Xenopus laevis cells.
abstract: We have examined the effect of 5'-methylthioadenosine (MTA) on RNA metabolism and DNA synthesis in a cultured Xenopus laevis epithelial cell line. Cells incubated in the presence of MTA were transcriptionally less active than controls as measured by the run-off transcription technique. Experiments which measured the percentage of newly-synthesized poly(A)+ RNA and alpha-amanitin-sensitive nuclear transcripts suggested that MTA inhibited transcription by both RNA polymerases I and II. DNA synthesis was observed to proceed normally at times when MTA inhibited RNA synthesis. These results suggest that the well-known anti-proliferative effect of MTA is due indirectly to its initial effects on the transcription of ribosomal RNA (rRNA) and messenger RNA (mRNA) rather than a direct suppression of DNA replication.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis*; D003839:Deoxyadenosines; D011061:Poly A / Q000378:metabolism; D012313:RNA / Q000096:biosynthesis* / Q000378:metabolism; D012318:RNA Polymerase I / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger; D013872:Thionucleosides / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*; D014982:Xenopus laevis
chemical_list: D003839:Deoxyadenosines; D012333:RNA, Messenger; D013872:Thionucleosides; D011061:Poly A; D012313:RNA; C008500:5'-methylthioadenosine; D004247:DNA; D012319:RNA Polymerase II; D012318:RNA Polymerase I; D000241:Adenosine