title: The cellular level of yeast ribosomal protein L25 is controlled principally by rapid degradation of excess protein.
abstract: 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.
authors.affiliation: Biochemisch Laboratorium, Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: T T
authors.initials: TT
authors.lastname: elBaradi
authors.forename: C A
authors.initials: CA
authors.lastname: van der Sande
authors.forename: W H
authors.initials: WH
authors.lastname: Mager
authors.forename: H A
authors.initials: HA
authors.lastname: Raué
authors.forename: R J
authors.initials: RJ
authors.lastname: Planta
mesh_terms: D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005784:Gene Amplification; D005800:Genes, Fungal; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D012322:RNA Precursors; D012331:RNA, Fungal; D012269:Ribosomal Proteins; C031127:ribosomal protein L25