Functional substitution of mouse ribosomal protein L27' for yeast ribosomal protein L29 in yeast ribosomes.

Abstract

A cDNA clone of mouse ribosomal protein L27' was shown previously to be 62% identical in amino acid residues to yeast ribosomal protein L29. The L27' cDNA was expressed in yeast to determine the ability of the mouse protein to substitute for yeast L29 in assembling a functional ribosome. In a yeast strain resistant to cycloheximide by virtue of a recessive mutation in the L29 protein, the murine cDNA did not produce a sensitive phenotype, indicating failure of the mouse L27' protein to assemble into yeast ribosomes. However, when the mouse L27' gene was expressed in cells devoid of L29 and otherwise inviable, the murine protein supported normal growth, demonstrating that mouse ribosomal protein L27' indeed was interchangeable with yeast L29. We conclude that mouse ribosomal protein L27' is assembled into ribosomes in yeast, but yeast L29 is assembled preferentially when both L29 and L27' are present in the same cell.The ribosome is an organelle whose constituent building blocks have been extensively catalogued. With identification of ribosomal components completed, attention has turned toward deducing the arrangement of the various protein and RNA moieties in the overall structure as well as assigning functions to individual or groups ofribosomal components. A particularly profitable means of determining the function of individual ribosomal components has been through genetic and biochemical analysis of mutants resistant or hypersensitive to inhibitors of protein synthesis (1, 2). Another approach has been in vitro reconstitution of ribosomes (3); omission of specific ribosomal proteins from reconstitution mixtures often results in absence of a specific function in the completed particles, thereby implicating the missing protein in that function (4)(5)(6). Although eukaryotic ribosomes have been reconstructed with groups ofribosomal proteins (7-9) or subunits (10)

A Drosophila ribosomal protein functions in mammalian cells.

“…Heterologous S14 is assembled into functional ribosomal subunits and renders the cells sensitive to emetine. In this respect our experiment differs significantly from a study recently described by Fleming et al (10). Those (20).…”

Rat RL23a Ribosomal Protein Efficiently Competes with itsSaccharomyces cerevisiaeL25 Homologue for Assembly Into 60 S Subunits

“…This is in clear contrast to previous experiments in which heterologous r-proteins failed to compete or competed very poorly with their endogenous counterpart, despite a comparable (Fleming et al, 1989) or even higher (Maki et al, 1990) degree of structural similarity.…”

Roles of the negatively charged N-terminal extension of Saccharomyces cerevisiae ribosomal protein S5 revealed by characterization of a yeast strain containing human ribosomal protein S5

“…To date there are only a few reports that a yeast ribosomal protein can be replaced with a mammalian (or insect) homolog. Yeast rpL25 can be replaced by rat and Drosophila melanogaster rpL23A (Jeeninga et al 1996;Ross et al 2007) and mouse ribosomal protein rpL279 can substitute for the yeast rpL29 (Fleming et al 1989). These replacements all involved the large (60S) ribosomal subunit.…”