The cellular level of yeast ribosomal protein L25 is controlled principally by rapid degradation of excess protein

Curr Genet. 1986;10(10):733-9. doi: 10.1007/BF00405095.


When the gene dosage for the primary rRNA-binding ribosomal protein L25 in yeast cells was raised about 50-fold, the level of mature L25 transcripts was found to increase almost proportionally. The plasmid-derived L25 transcripts were structurally indistinguishable from their genomic counterparts, freely entered polysomes in vivo and were fully translatable in a heterologous in vitro system. Nevertheless, pulse-labelling for periods varying from 3-20 min did not reveal a significant elevation of the intracellular level of L25-protein. When pulse-times were decreased to 10-45 s, however, we did detect a substantial overproduction of L25. We conclude that, despite the strong RNA-binding capacity of the protein, accumulation of L25 is not controlled by an autogenous (pre-)mRNA-targeted mechanism similar to that operating in bacteria, but rather by extremely rapid degradation of excess protein produced.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Gene Amplification
  • Genes, Fungal
  • RNA Precursors / genetics
  • RNA Precursors / metabolism
  • RNA, Fungal / genetics
  • RNA, Fungal / metabolism
  • Ribosomal Proteins / genetics
  • Ribosomal Proteins / metabolism*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*


  • Fungal Proteins
  • RNA Precursors
  • RNA, Fungal
  • Ribosomal Proteins
  • ribosomal protein L25