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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Merodiploid strains of Escherichia coli containing episomes which carry one or several of the ribosomal protein (r-protein) transcriptional units were analysed to see whether the increase in the number of gene copies leads to an increased synthesis of the respective r-proteins. It was found that the amount of ribosomal proteins was (with the only exception of ribosomal protein S20) independent of the number of gene copies present. The comparison of the in vivo stability of r-proteins in haploid and merodiploid strains did not, within the time resolution of the experiment, provide any evidence for an increased rate of degradation of those proteins coded by more than one gene copy. These results indicate a tight coupling between the amount of ribosomal proteins synthesized and the level required irrespective of the number of gene copies present. With the aid of minicells from a strain containing the episome F'101 which carries the thr-leu segment of the chromosome it was demonstrated that (i) in vivo synthesis of r-protein S20 could proceed in the absence of the synthesis of ribosomal RNA and of other r-proteins, and (ii) r-protein S20 was degraded under conditions where it was not assembled into ribosomes.
Mol Gen Genet 1977 Sep 09
PMID:Synthesis of ribosomal proteins in merodiploid strains and in minicells of Escherichia coli. 33 11

A method to obtain amber mutations in ribosomal protein genes is described. tit relies on the P1-mediated localized mutagenesis (Hong and Ames, 1971) and on the fact that the recipient strain contains (a) an efficient but genetically unstable suppressor, (b) a particular thermoinducible lambda prophage which kills suppressor hosts at 42 degrees C. Exposure of these bacteria to the high temperature yields frequent suppressor-free derivatives while none will be found if the strain carries an amber mutation in an essential gene. Eleven mutants have been isolated by this method, of which at least six appear to carry amber mutations. All of them map close to, and to the right of spcA, in a region which codes mostly for ribosomal proteins. Three mutants were studied biochemically; all three show defective ribosomal assembly in vivo upon loss of suppression.
Mol Gen Genet 1977 Nov 29
PMID:Amber mutations in Escherichia coli essential genes: isolation of mutants affected in the ribosomes. 34 Sep 21

The formation and repressibility of the arginine biosyntietic enzymes acetylornithine delta-aminotransferase (EC 2.6.1.11), acetylornithine deacetylase (EC 3.5.1.16), ornithine carbamoyltransferase (EC 2.1.3.3), and argininosuccinate lyase (EC 4.3.2.1) were studied in an Escherichia coli W derivative (strain 250-10) that carries (a) a mutant allele of the argR regulatory gene causing a diminished repression-derepression range and (b) a streptomycin resistance mutation. In comparison with the streptomycin-sensitive parent 250, all four enzymes (a) are formed as smaller proportions of the total protein (overall range, 12% to 71%), whether the conditions are repressive (arginine excess) or derepressive (arginine restriction), and (b) show increased repressibility ratios, the carbamoyltransferase giving the largest increase (from 5.7 to 25.0). These effects appear to depend on the concurrent expression of the regulatory-gene and streptomycin resistance mutations, as indicated by analogous experiments with canavanine-resistant mutants of 250-10 that have partial argR- character. The results provide evidence for translational repression in the arginine system, and are interpreted in terms of a functional interaction of a mutant arginine repressor with a mutant S12 ribosomal protein. The locale of translational repression may be near the site of S12, and this mode of regulation may involve initiational selectivity of groupwise recognizable arginine messenger RNA's.
Mol Gen Genet 1978 Jun 14
PMID:Evidence for translational repression of arginine biosynthetic enzymes in Escherichia coli: altered regulation in a streptomycin-resistant mutant. 35 28

The ribosomal protein patterns of recessive suppressor strain and parent strain of Saccharomyces cerevisiae were analyzed by two-dimensional polyacrylamide gel electrophoresis. About 30 proteinspots were found for ribosomal proteins of small subunit for both mutant and parent strain. These patterns do not differ from each other neither in intensity of staining, nor in mobility of spots. 41 protein spots were found in electrophoregrams of 60S ribosomal proteins both from parent strain and recessive suppressor strain. The electrophoretic picture of the 60S proteins from the parent and mutant strains is similar except the intensity of staining of the L30 spot. This protein is present in 60S subunit of suppressor strain and completely absent or only weakly stained on electrophoregrams of ribosomal proteins of parent strain. The possible relationships between the content of L30 protein and the mechanism of recessive suppression in yeast are discussed.
Mol Gen Genet 1978 Jul 06
PMID:Recessive nonsense-suppression in yeast: involvement of 60S ribosomal subunit. 35 43

A strain of Escherichia coli, VT, which spontaneously gives rise to mutations in many ribosomal proteins, has been used in conjunction with chemical mutagenesis and varying the subsequent incubation temperature to select mutants which have alterations in every ribosomal protein amenable to analysis of 70 S proteins on two-dimensional polyacrylamide gels under standard conditions. Alterations have been detected in 50 ribosomal proteins, namely in 20 from the small and in 30 from the large subunit. This is the most complete set of mutants with altered ribosomal proteins described so far. The difficulty until recently in obtaining mutations in most ribosomal proteins arises not because they are lethal, as has often been supposed, but because of the lack of a suitable selection heretofore.
Mol Gen Genet 1978 Sep 20
PMID:Mutational alterations in 50 proteins of the Escherichia coli ribosome. 36 67

A mutant of Escherichia coli which was isolated for temperature-sensitive growth was found to harbour a structural alterations in protein S16 (Isolo et al., 1978). The mutation was localized by matings with various Hfr strains and by Plkc-mediated transduction. The results showed that it mapped very close to the gene coding for L19 protein which has been placed at 56.4 min (Kitakawa and Isono, 1977), indicating that it most likely forms a new ribosomal protein-gene cluster.
Mol Gen Genet 1978 Oct 24
PMID:Genes encoding ribosomal proteins S16 and L19 form a gene cluster at 56.4 min in Escherichia coli. 36 62

Analysis of the synthetic rate of individual protein species at various times after complete inhibition of transcription with either streptolygidin or rifampicin was carried out by two-dimensional polyacrylamide electrophoresis of total Escherichia coli cell extracts. The decay rate of the potential to synthesize different proteins was assumed to be equal to the functional decay rate of the corresponding mRNA. We conclude the following: (a) The tufA and tufB messengers have different half lives (3.0 and 2.4 min, respectively). (b) Different genes within the same transcriptional unit can have different half lies (S7, EGF and EFTuA--2.5, 3.8 and 3.0 min, respectively). (c) There is at least a twenty-fold variation in individual mRNA half lives in E. coli; ribosomal protein S1 mRNA was observed to have the shortest half life in the cell (40 sec), while the longest observed half life was approximately 20 min (all values at 30 degrees C). (d) Addition of rifampicin increases the absolute rate of RNA polymerase subunit alpha and beta synthesis two-fold. (e) The induction of the synthesis of alpha subunit of RNA polymerase takes place without a concomitant induction of ribosomal protein S4 and L17, which are reported to be on either side of alpha in the same transcriptional unit.
Mol Gen Genet 1978 Nov 09
PMID:Functional mRNA half lives in E. coli. 36 81

Two genes governing ribosomal protein methylation have been located on the map of Escherichia coli by conjugation and transduction crosses between wild-type and prm (protein methylation) mutants. The Prm phenotype of recombinants was determined by an in vitro assay of methylgroups incorporation into protein. Gene prmA, governing methylation of protein L11 is situated at minute 71 on the map and is cotransduced with aroE (30%) and with rpsL (5%). Gene prmB, governing methylation of protein L3 is at minute 50, very close to aroC (98.5% co-transduction). A cold-sensitive phenotype was found associated with mutation prmB and was used to score a large number of recombinants in a three factor cross. The results of this cross suggest the order aroC -prmB - purF. The striking symmetrical clustering of aro, prm and rim (ribosome maturation) genes is discussed.
Mol Gen Genet 1979 Feb 01
PMID:Genetics of ribosomal protein methylation in Escherichia coli. III. Map position of two genes, prmA and prmB, governing methylation of proteins L11 and L3. 37 46

Polyuridilic acid of average molecular weight 18 000 binds to the 30S subunits with stoichiometry 1 : 1 but two kinds of 30S.poly(U) complexes with different stability are formed. The main reason for such heterogeneity was found to be due to the presence or absence of ribosomal protein Sl in 30S subunits. In its presence the association constant of 30S.poly(U) complex is equal 2.7.10(8) M-1, and in the opposite case it is much less 1.5.10(6) M-1. In the same conditions (20 mM MgCl2, 200 mM HN4Cl, 0 degrees) the association constant of binary complex Sl.poly(U) is equal 5.10(7) M-1.
Mol Biol (Mosk)
PMID:[Quantitative studies of interaction of polyuridylic acid with 30S subunits of ribosomes of Escherichia coli]. 37 17

A temperature sensitive mutant, termed JE1306, derived from Escherichia coli strain PA3092 was found to have an alteration in the ribosomal protein L25. Crosses with various Hfr strains and transductions with P1 kc phage have revealed that the mutation maps at 47.3 min between nalA and fpk, in a region where no ribosomal protein gene has so far been located. The gene affected by this mutation is most probably the structural gene for protein L25 (rplY), because a strain heteromerozygous for the region shows both wild type and mutant forms of protein L25.
Mol Gen Genet 1979 Nov
PMID:The gene for ribosomal protein L25 (rplY) maps at 47.3 min near nalA in Escherichia coli K-12. 39 36


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