Synthesis and incorporation of human ribosomal protein S14 into functional ribosomes in human-Chinese hamster cell hybrids containing human chromosome 5: human RPS14 gene is the structural gene for ribosomal protein S14

Abstract

In Chinese hamster ovary cells, mutations in the RPS14 gene (which was previously designated emtB) render cells resistant to normally cytotoxic concentrations of the protein synthesis inhibitor, emetine. Several lines of evidence indicate the RPS14 gene in Chinese hamster is the structural gene for ribosomal protein S14, including the finding that mutants with alterations in this gene produce an electrophoretically altered form of this protein. A human gene which complements the defect in CHO RPS14 mutants and renders them sensitive to emetine has previously been assigned to the long arm of chromosome 5. The analysis of ribosomal proteins extracted from CHO Emtr X human cell hybrids, which contain human chromosome 5 and are emetine sensitive, demonstrated the presence of both the normal human and altered hamster forms of ribosomal protein S14. Human chromosome 5, the emetine-sensitive phenotype, and the human form of ribosomal protein S14 segregate concordantly from hybrids, confirming that the human gene in question is the structural gene for this protein. In addition, the results indicate that in interspecific cell hybrids, the human form of S14 is either incorporated into functional ribosomes more efficiently than the altered hamster protein or the human gene is overexpressed relative to the corresponding hamster gene.