scholarly journals Emetine resistance in Chinese hamster cells is linked genetically with an altered 40S ribosomal subunit protein, S20.

1979 ◽  
Vol 76 (1) ◽  
pp. 415-419 ◽  
Author(s):  
D. Boersma ◽  
S. M. McGill ◽  
J. W. Mollenkamp ◽  
D. J. Roufa

1990 ◽  
Vol 111 (6) ◽  
pp. 2261-2274 ◽  
Author(s):  
M Moritz ◽  
A G Paulovich ◽  
Y F Tsay ◽  
J L Woolford

Two strains of Saccharomyces cerevisiae were constructed that are conditional for synthesis of the 60S ribosomal subunit protein, L16, or the 40S ribosomal subunit protein, rp59. These strains were used to determine the effects of depriving cells of either of these ribosomal proteins on ribosome assembly and on the synthesis and stability of other ribosomal proteins and ribosomal RNAs. Termination of synthesis of either protein leads to diminished accumulation of the subunit into which it normally assembles. Depletion of L16 or rp59 has no effect on synthesis of most other ribosomal proteins or ribosomal RNAs. However, most ribosomal proteins and ribosomal RNAs that are components of the same subunit as L16 or rp59 are rapidly degraded upon depletion of L16 or rp59, presumably resulting from abortive assembly of the subunit. Depletion of L16 has no effect on the stability of most components of the 40S subunit. Conversely, termination of synthesis of rp59 has no effect on the stability of most 60S subunit components. The implications of these findings for control of ribosome assembly and the order of assembly of ribosomal proteins into the ribosome are discussed.



1983 ◽  
Vol 3 (2) ◽  
pp. 190-197
Author(s):  
J J Madjar ◽  
M Frahm ◽  
S McGill ◽  
D J Roufa

Four two-dimensional polyacrylamide gel electrophoresis systems were used to identify 78 Chinese hamster cell ribosomal proteins by the uniform nomenclature based on rat liver ribosomal proteins. The 40S ribosomal subunit protein affected by Chinese hamster ovary (CHO) cell one-step emetine resistance mutations is designated S14 in the standard nomenclature. To seek unambiguous genetic evidence for a cause and effect relationship between CHO cell emetine resistance and mutations in the S14 gene, we mutagenized a one-step CHO cell mutant and isolated second-step mutant clones resistant to 10-fold-higher concentrations of emetine. All of the highly resistant, two-step CHO cell mutants obtained displayed additional alterations in ribosomal protein S14. Hybridization complementation tests revealed that the two-step CHO cell emetine resistance mutants were members of the same complementation group defined by one-step CHO cell mutants, EmtB. Two-step mutants obtained from a Chinese hamster lung cell emetine-resistant clone belong to the EmtA complementation group. The two-step and EmtB mutants elaborated 40S ribosomal subunits, which dissociated to 32S and 40S core particles in buffers containing 0.5 M KCl at 4 degrees C. In contrast, 40S ribosomal subunits purified from all EmtA, one-step EmtB EmtC mutants, and wild-type CHO and lung cells were stable at this temperature in buffers containing substantially higher concentrations of salt. Thus, two-step emtB mutations affect the structure of S14 protein directly and the stability of the 40S ribosomal subunit indirectly.



Biochimie ◽  
1992 ◽  
Vol 74 (4) ◽  
pp. 363-371 ◽  
Author(s):  
O.A. Dontsova ◽  
K.V. Rosen ◽  
S.L. Bogdanova ◽  
E.A. Skripkin ◽  
A.M. Kopylov ◽  
...  


1985 ◽  
Vol 5 (7) ◽  
pp. 1655-1659
Author(s):  
D D Rhoads ◽  
D J Roufa

The Chinese hamster ovary (CHO) cell 40S ribosomal subunit protein S14 provides a unique opportunity to investigate an important mammalian housekeeping gene and its mRNA and protein products. The S14 gene appears to be single copy, and CHO cell S14 mutants have been isolated as emetine-resistant (emtB) clones in tissue culture. Thus, S14 is the only mammalian ribosomal protein whose gene structure and function are amenable to straightforward genetic and biochemical analysis. Recently, we isolated a wild-type Chinese hamster lung cell cDNA clone, pCS14-1, including an almost complete copy of the ribosomal protein S14 message (N. Nakamichi, D. D. Rhoads, and D. J. Roufa, J. Biol. Chem. 258: 13236-13242, 1983). Here we describe comparable cDNAs from wild-type and emtB CHO cells. We report both mRNA and polypeptide sequences of the wild-type and mutant ribosomal protein transcripts. As a consequence of the genetic methods used to obtain our emetine-resistant mutants, the emtB S14 cDNAs differ from wild-type cDNA by single-base changes. Physical and chemical features of polypeptides encoded by the cDNAs are consistent with well-characterized S14 protein polymorphisms. The three emtB mutations analyzed affect two adjacent arginine codons within the very basic S14 carboxyl region, indicating a significant role for this portion of the protein in the function and architecture of the mammalian 40S ribosomal subunit.



1985 ◽  
Vol 5 (7) ◽  
pp. 1655-1659 ◽  
Author(s):  
D D Rhoads ◽  
D J Roufa

The Chinese hamster ovary (CHO) cell 40S ribosomal subunit protein S14 provides a unique opportunity to investigate an important mammalian housekeeping gene and its mRNA and protein products. The S14 gene appears to be single copy, and CHO cell S14 mutants have been isolated as emetine-resistant (emtB) clones in tissue culture. Thus, S14 is the only mammalian ribosomal protein whose gene structure and function are amenable to straightforward genetic and biochemical analysis. Recently, we isolated a wild-type Chinese hamster lung cell cDNA clone, pCS14-1, including an almost complete copy of the ribosomal protein S14 message (N. Nakamichi, D. D. Rhoads, and D. J. Roufa, J. Biol. Chem. 258: 13236-13242, 1983). Here we describe comparable cDNAs from wild-type and emtB CHO cells. We report both mRNA and polypeptide sequences of the wild-type and mutant ribosomal protein transcripts. As a consequence of the genetic methods used to obtain our emetine-resistant mutants, the emtB S14 cDNAs differ from wild-type cDNA by single-base changes. Physical and chemical features of polypeptides encoded by the cDNAs are consistent with well-characterized S14 protein polymorphisms. The three emtB mutations analyzed affect two adjacent arginine codons within the very basic S14 carboxyl region, indicating a significant role for this portion of the protein in the function and architecture of the mammalian 40S ribosomal subunit.



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