Nuclear retention of the induced mRNA following amino acid-dependent transcriptional regulation of mammalian ribosomal proteins L17 and S25.

摘要: Abstract An amino acid starvation-induced mRNA, increased up to 4-fold in the absence of acids, was identified previously as rat 60 S subunit ribosomal protein L17. The data presented here demonstrate that among proteins, L17, well smaller S25, are uniquely regulated by deprivation cells; increase L17 and S25 mRNA content response substrate starvation is not shared 11 other proteins tested. When Fao hepatoma cells were incubated presence actinomycin D, level decayed below basal level, regardless medium content, nuclear run-off assays confirmed nutrient leads enhanced transcription gene. Likewise, induction also prevented D. Furthermore, blocked cycloheximide, demonstrating requirement for a newly synthesized signaling pathway. Northern analysis with RNA isolated from cytoplasmic, polysomal, enriched fractions indicated starvation-dependent mRNAs retained within nucleus available translation. Amino refeeding caused translocation stored polysomal fraction.