Search tips
Search criteria 


Logo of molcellbPermissionsJournals.ASM.orgJournalMCB ArticleJournal InfoAuthorsReviewers
Mol Cell Biol. 1985 December; 5(12): 3436–3442.
PMCID: PMC369173

Posttranscriptional regulation and assembly into ribosomes of a Saccharomyces cerevisiae ribosomal protein-beta-galactosidase fusion.


To study the regulation of ribosomal protein genes, we constructed a 'lacZ fusion of the Saccharomyces cerevisiae RP51A gene, containing the first 64 codons of RP51A. In a strain lacking an intact RP51A gene (cells are viable due to the presence of an active RP51B gene), beta-galactosidase activity is 10-fold greater than in a strain containing RP51A. RP51A-lacZ mRNA levels are equal in the two strains, indicating that regulation is posttranscriptional. In the absence of the RP51A gene, the fusion protein is predominantly cytoplasmic and associated with polysomes, whereas in the presence of RP51A, the fusion protein is predominantly nuclear, and none is associated with polysomes. Deletions were made in the RP51A-coding portion of the fusion gene. The most extensively deleted gene, containing only the first seven RP51A codons fused to lacZ, produced a high level of beta-galactosidase activity in both the presence and the absence of the RP51A gene. In both cases, little or none of this shorter fusion protein was found associated with polysomes. Thus, a regulatory site (or sites) lies in the protein-coding region of RP51A. We suggest that posttranscriptional regulation of the rp51 fusion protein is related to assembly of the protein into ribosomes.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.4M), or click on a page image below to browse page by page.

Images in this article

Click on the image to see a larger version.

Articles from Molecular and Cellular Biology are provided here courtesy of American Society for Microbiology (ASM)