Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The synthesis of tRNA in yeast is shown to be under separate control to that of rRNA during amino acid and nitrogen starvation. Inhibitors of the elongation and termination steps of protein synthesis were found to stimulate the synthesis of tRNA in starved yeast cells. This effect appeared to be due to the "trickle-charging" of tRNA. Two inhibitors of early steps in the initiation of protein synthesis were found to be unable to stimulate RNA synthesis in starved cells. It is proposed that yeast tRNA synthesis is under autoregulatory control and that the level of tRNA charging and the mRNA-ribosome complex are important components of this control system.
Mol Gen Genet 1977 Jul 20
PMID:The regulation of RNA synthesis in yeast. I: Starvation experiments. 33 Oct 81

Escherichia coli, cultured on minimal medium and deprived of its required amino-acids, was induced for lac genes transcription. After inducer removal and restoration of growth, beta-galactosidase synthesis was measured. Two different kinetics of enzyme synthesis were observed depending on the starvation conditions employed during the induction period: 1. beta-galactosidase synthesis was immediately obtained and a plateau was reached, in 20 min after restoration of growth, when cells had been induced during deprivation of amino-acids and carbon source. 2. beta-galactosidase displayed an unusually long rate of synthesis, and plateau was not reached before two doubling times, when cells had been induced during the deprivation of the sole amino-acids. The latter result points out a problem of messenger stability during those long translation kinetics and led us to study the behaviour of strains carrying lac genetic determinants on different replicative structures; chromosomic and plasmidic. In those two situations, induction of lac messenger RNA was obtained and ratify our previous observations. However, their translation kinetics suggest a DNA linkage of this induced messenger.
Mol Gen Genet 1977 Nov 14
PMID:Unusual stability and translation kinetics of an Escherichia coli lac messenger RNA synthetized during amino-acids deprivation. 34 Sep 4

Mutants of LexB have been isolated by their resistance to lysogenic induction by thymine starvation, their resistance to thymine starvation and on the basis of their UV sensitivity. Here, three mutations identified originally in strains lacking mutagenic response to UV-irradiation, unmB (Kato and Shinoura, 1977), have been further characterized, mapped by P1-mediated transduction with srl into the recA-tif-zab-lexB cluster at the lexB position and analysed for complementation with various lexB and recA mutations. From the results it was concluded that unmB mutations are identical to lexB mutations; consequently these mutations have been termed lexB32, lexB33 and lexB35. The mutations lexB33 and lexB35 do not complement any of the other lexB mutations and define therefore a new complementation type. The lexB32 mutation, which like the lexB34 mutation, results in moderate UV sensitivity has a complementation pattern similar to that of lexB34. However, unlike lexB34 the lexB32 behaves like a leaky mutation. The results are discussed in relation to the recA gene product and its control.
Mol Gen Genet 1977 Nov 29
PMID:The genetic characterization of lexB32, lexB33 and lexB35 mutations of Escherichia coli: location and complementation pattern for UV resistance. 34 Sep 15

The ribosomal proteins of 11 mutants which are sensitive to starvation at elevated temperature and of 36 transductants derived from them were studied with several electrophoretic, immunochemical and proteinchemical methods. The following results were obtained: (1) Ribosomal protein S8 is altered in three of these mutants. (2) The amino acid exchange in proteins S8 of mutant N4128 is Glu leads to Lys in position 59 of the protein chain. (3) Temperature sensitivity and inability to recover from starvation at elevated temperatures are caused by the same mutational event which is, however, unrelated to the alteration in protein S8. Several electrophoretic and immunological procedures were applied during the characterization of these mutants. A modified immunoelectrophoresis on cellulose acetate gels was developed, and proved to be the most applicable procedure for the detection of mutationally altered ribosomal proteins. This procedure may gain general importance for detecting mutational alterations in other proteins.
Mol Gen Genet 1977 Dec 30
PMID:Improved electrophoretic and immunochemical techniques for the identification and characterization of mutant proteins, applied to ribosomal protein S8 in Escherichia coli mutants. 34 Sep 33

Thymidylate starvation in a yeast mutant auxotrophic for dTMP caused cell death and the induction of mutations in the mitochondrial genome. After 24 h of starvation almost all surviving cells were respiratory deficient petites. In addition, shorter episodes of dTMP starvation induced chloramphenicol and erythromycin resistant mutants, indicating the occurrence of mitochondrial point mutations. Suboptimal concentrations of exogenous thymidylate were also found to induce petites and a decline in cell viability and the magnitude of these effects was acutely dependent upon the dTMP concentration. Cesium chloride gradient analysis of DNA from cells undergoing thymineless incubation revealed a progressive loss of mitochondrial DNA, and a decrease in the molecular weight of nuclear DNA.
Mol Gen Genet 1978 Mar 20
PMID:Genetic damage during thymidylate starvation in Saccharomyces cerevisiae. 34 46

A relA+ strain of E. coli with four amino acid requirements was starved separately for each amino acid, after which the levels of polysomes, guanosine-5'-diphosphate-3'-diphosphate and the residual net synthesis of RNA were determined. The polysome level and guanosine-5'-diphosphate-3'-diphosphate production were coordinately affected by starvation for the different amino acids, whereas no correlation was found between these two parameters and residual RNA synthesis. The main conclusion stemming from these results is that guanosine-5'-diphosphate-3'-diphosphate cannot act as the sole effector molecule in stringent control of RNA synthesis.
Mol Biol Rep 1978 Feb 28
PMID:The relationship between guanosine tetraphosphate, polysomes and RNA synthesis in amino acid starved Escherichia coli. 34 53

The simultaneity of the presence of substrate (inducer) and the absence of a better nitrogen nutrient causes a strong cooperative effect (catabolic synergism) on arginase production. This effect is shown to operate by a specific mechanism. carg A+ 0h mutation (Dubois et al., 1978) identifies an element of this process located near the arginase structural gene and acting in cis. This mutation produces constitutivity for synergism in addition to constitutivity for induction (this last effect is produced alone by cargA +0- operator constitutive mutation). The receptor of the signal for the presence of substrate is the same as for induction. cargA + 0h mutation allows to make further distinction between the promotion of arginase synthesis caused by nitrogen limitation and nitrogen starvation.
Mol Gen Genet 1978 Sep 08
PMID:Catabolic synergism: a cooperation between the availability of substrate and the need for nitrogen in the regulation of arginine catabolism in Saccharomyces cerevisiae. 36 56

Upon addition of excess one carbon metabolites (including serine)bacteria stop growing because of isoleucine starvation. After such treatment stringent bacteria rapidly resume normal growth whereas relaxed mutants remain unable for some time to grow. We show here that this is due to a lack of derepressibility of ilv genes after the starvation period. Results are also presented which show that RNA polymerase structural mutants may be selected among the clones resistant to a mixture of serine, methionine and glycine, in relA- strains. Finally circumstancial evidence suggests that the one carbon metabolism may be involved in a process controlling isoleucine metabolism.
Mol Gen Genet 1978 Sep 20
PMID:Correlation between the serine sensitivity and the derepressibility of the ilv genes in Escherichia coli relA- mutants. 36 63

Normally, bacteria cease DNA replication in the absence of protein synthesis. A variety of treatments, such as thymine starvation or a shift-up to rich medium, lead to continued DNA replication in the absence of protein synthesis. Mutants are described which always terminate replication under these conditions. These conditional lethal mutants, dnaT1 and dnaT2, contransduce with serB and dnaC. The mutation also affects cell division. All aspects of the mutant phenotype (obligatory termination of replication, temperature sensitivity of DNA replication and growth, and aberrant cell division at permissive growth temperatures) were transdominant to the wild-type phenotype. Episomes carrying the dnaT mutation appeared to be unstable. The existence of such a dominant mutation was predicted by a model of chromosome termination proposed by Kogoma and Lark (J. Mol. Biol. 94:243-256, 1975).
 ...
PMID:dnaT, dominant conditional-lethal mutation affecting DNA replication in Escherichia coli. 36 84

A new class of mutants of E. coli exhibiting altered metabolism of ppGpp and pppGpp has been isolated, and mapped at a locus designated gpp, near min 83 on the genetic map. These mutants accumulate elevated levels of pppGpp during amino acid starvation or carbon source downshift, and exhibit a reduced rate of pppGpp degradation in vivo. The in vitro evidence suggests that the gpp mutants are defective in a 5'-nucleotidase, which specifically hydrolyzes pppGpp to ppGpp. Certain combinations of gpp and spoT mutations are inviable. A gpp spoT double mutant, constructed by employing a leaky spoT mutation, was found to have a slower rate of pppGpp degradation than the gpp mutant alone. This result indicates that spoT also participates in pppGpp degradation. The inviability of certain gpp spoT combinations is attributed to the inability of the double mutants to degrade pppGpp. This is supported by the observation that selection for increased growth rate on the double mutant results in the recovery of relA mutations. Various effects of the gpp mutation upon the pppGpp and ppGpp pools provide additional support for a scheme in which pppGpp is the major precursor of ppGpp.
Mol Gen Genet 1979 Feb 01
PMID:Mutants of Escherichia coli defective in the degradation of guanosine 5'-triphosphate, 3'-diphosphate (pppGpp). 37 53


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>