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

An isogenic pair of Escherichia coli strains, one carrying an rnc+ and the other an rnc- allele (a mutation which reduces the level of ribonuclease III), was compared. The rnc- strain fails to grow at very elevated temperatures (for E. coli) while the rnc+ strain does grow exponentially. Assaying the residual RNase III like activity in extracts of the rnc- strain at different pHs and at different temperatures suggested that this residual RNase III like activity is not due to RNase III. This raised the possibility that the rnc- strain is devoid of any RNase III activity in the cell. Comparing the decay of newly synthesized RNA and functional decay of beta-galactosidase mRNA in such strains revealed that in both strains these parameters proceed in similar rates, which suggests that RNase III is not involved in the metabolism of mRNA. During carbon starvation preexisting total RNA, as well as 23S and 16S rRNA, decay faster in the rnc- strain, thus eliminating the possibility that RNase III is the endoribonuclease which initiates the decay of rRNA during starvation (Kaplan and Apirion, 1975a).
Mol Gen Genet 1976 Mar 22
PMID:Consequences of losing ribonuclease III on the Escherichia coli cell. 77 91

When growing cultures of S. cerevisiae are treated with high concentrations of ethidium bromide (greater than 50 mug/ml), three phases of petite induction may be observed: I. the majority of cells are rapidly converted to petite, II. subsequently a large proportion of cells recover the ability to form respiratory competent clones, and III. slow, irreversible conversion of all cells to petite. The extent of recovery of respiratory competence observed is dependent on the strain of S. cerevisiae employed and the temperature and the carbon source used in the growth medium. The effects of 100 mug/ml ethidium bromide are also produced by 10 mug/ml ethidium bromide in the presence of the detergent, sodium dodecyl sulphate, and recovery is also observed when cells are treated with 10 mug/ml ethidium bromide under starvation conditions. Genetic analysis of strain differences indicates that a number of nuclear genes influence petite induction by ethidium bromide. In one strain, S288C, petite induction by 100 mug/ml ethidium bromide is extremely slow under certain conditions. Mitochondria isolated from from S288C lack the ethidium bromide stimulated nuclease activity found in D243-4A, a strain which shows triphasic kinetics of petite formation. This enzyme may, therefore, be responsible for the initial phase of rapid petite formation.
Mol Gen Genet 1976 Mar 30
PMID:Factors affecting petite induction and the recovery of respiratory competence in yeast cells exposed to ethidium bromide. 77 97

A temperature sensitive mutant of Escherichia coli which fails to recover from prolonged carbon starvation, was found to be irreversibly killed by exposure to a nonpermissive temperature (43 degrees C), with a half-life of about half an hour. This bacteriocidal effect of the temperature could be reversed by a number of antibiotics which block protein synthesis but not by blocking DNA synthesis. At the nonpermissive temperature, RNA and the protein synthetic capacities decrease before the DNA synthetic capacity is decreased. Analysis of ribosomal proteins and methylation of them did not reveal any consistent differences between the parental and mutant strains. Analysis of the ribosomal RNA revealed that it is being synthesized in similar amounts as in the parental strain at the nonpermissive temperature, however, after chase its level is decreased. Moreover, the 17S precursor RNA is slow to mature to 16S rRNA in the mutant strain at the nonpermissive temperature. Thus, these studies suggest that the mutation studied here affects a late maturation step in the synthesis of the rRNA. Therefore the gene is designated rimH (for ribosomal modification). All the properties bestowee on the mutant strain are caused by a single pleiotropic mutation which maps at min 14 of the E. coli map. Three point transduction crosses suggest the order rimH, leuS, RNA, LIP. This gene maps outside the two known clusters for ribosomal structural genes.
Mol Gen Genet 1976 Aug 10
PMID:A lethal mutation which affects the maturation of ribosomes. 78 23

Escherichia coli K12 Hfr H Tsxs Strs and F- Pro- Tsxr His- Arg- Strr bacteria were conjugated in the absence of arginine with or without glucose. The efficiency of conjugation, measured by the frequency of Pro+ and His+ recombinants was not affected. Arginine starvation alone did not affect the tsxs gene expression which occurred in all the zygotes which had received the gene. In contrast, argine and glucose starvation allows tsxs expression only in those zygotes in which the donor gene had been integrated in the genome. As the glucose starvation brings on a destabilization of the messenger RNA synthesized by the F- cells in absence of arginine, the results can be interpreted as follows: the transferred tsxs genes are transitorily expressed in all the zygotes at the unintegrated state. After this transient period, only thsoe genes integrated in the chromosomes of the zygotes continue to be expressed.
Mol Gen Genet 1976 Aug 10
PMID:Effect of glucose starvation on the expression of transferred tsx genes in Escherichia coli K12 zygotes. 78 25

Crosses were made using strains of S. cerevisiae which carried mitochondrial markers conferring resistance to erythromycin and chloramphenicol. The effect of auxotrophic starvation of one parent prior to mating on the transmission of its mitochondrial markers was studied in different crosses relative to the presence of the cdc8 nuclear mutation (a temperature-sensitive DNA replication). In crosses between two cdc8 mutant strains, auxotrophic starvation of one of the haploid parental stains prior to mating caused a marked decrease of its mitochondrial marker transmission to the diploid progeny of the cross. The transmission decreased as a function of the time of starvation. This effect was not observed in the cross between two wild type strains and in crosses of starved cdc8 phenotypic revertants with cdc8 mutant strains. Only a small, if any, effect of starvation on mitochondrial marker transmission was observed when starved cdc8 mutant strains were crossed either with their phenotypic revertants or with the wild-type strains. In one of the haploid parental strains the starvation increased the frequency of petites as a function of starvation time, while in the other this effect was not observed. In the progeny of cdc8 X cdc8 crosses (both in starvation experiments and in control crosses) an increased frequency of diploid petite cells accompanied by a decreased frequency of recombination between mitochondrial markers was noticed. The influence of the cdc8 mutation on the transmission of mitochondrial markers is discussed in terms of high frequency of p- molecule formation in cdc8 strains.
Mol Gen Genet 1976 Oct 18
PMID:Effect of auxotrophic starvation of mitochondrial marker transmission in the cdc8 mutant of Saccharomyces cerevisiae. 79 82

The transcriptional and translational events occurring during the induction of the lac operon, were separated by blocking the translational step, either by aminoacid starvation or by addition of chloramphenicol. It was found that the carbon source used during the subsequent translation, affected the rate of beta-galactosidase synthesis. A decoordination effect on the production of enzymes of the lac system was also observed in high catabolite repression media, as well as in nitrogen limiting conditions. These findings suggested a similarity with the polarity phenomenon. In order to test this similarity, polarity suppressors of a Z- polar mutant were isolated. In one of these mutants, probably suA like, no carbon source effect was observed during the translational step. The induction kinetics in different media, after distinct pregrowth conditions, supported the idea that this mutant could be considered catabolite repression resistant only in certain restrictive conditions.
Mol Gen Genet 1976 Oct 18
PMID:Catabolite translational effects on the lac messenger RNA of Escherichia coli K12. 79 85

An isogenic pair of Escherichia coli mutants (relA+ tufB valSts and relA1 tufB valSts) has been cultured at several temperatures to establish various degrees of limitation for valyl-tRNA synthetase. The biosynthetic rate of 16 identifiable proteins, most of which are components of the transcription and translation apparatus, was measured by pulse-labelling with [35S]-methionine, followed by protein separation using two-dimensional gel electrophoresis (O'Farrell, 1975). No single pattern of response to amino acid starvation of biosynthetic rate was observed. EF-Ts, L12 and S6 were found to be under strong stringent and relaxed regulation; EF-G, EF-Tu-A and S1 are under strong stringent, but weak relaxed regulation; EF-Tu-B, alpha, VRS, IRS and ARS are under week stringent and weak relaxed regulation; beta is under weak stringent regulation and does not respond at all to relaxed conditions; the biosynthetic rate of a protein called stringent starvation protein is strongly stimulated, relative to other proteins, in the starved stringent strain.
Mol Gen Genet 1976 Dec 22
PMID:Biosynthetic regulation of individual proteins in relA+ and relA strains of Escherichia coli during amino acid starvation. 79 46

The rate of DNA synthesis in cells precursors of the bone marrow of 15 psychic patients was studied by tritiated thymidine autoradiography during different periods of whole alimentary starvation (duration 28 days) which was used with the aim of therapy. It was shown that starvation induced rapid, "leap", "uneven" block of DNA synthesis and decrease in mitotic index. It was found that DNA synthesis block was marked with different degree in different marrow cells. It was supposed that DNA synthesis block occured mainly during G1--S period of interphase. During the initial period of refeeding, intensification of DNA synthesis, which preceded to sharp increase in mitotic index, was observed.
Mol Biol (Mosk)
PMID:[Effect on the whole alimentary starvation on DNA synthesis in cells precursors in human bone marrow]. 105 49

Quantitative measurements of alkaline phosphatase activity in various merozygotic combinations and electrophoretic analyses of periplasmic proteins derepressed by phosphate-starvation show that phoB is a positive regulatory gene.
Mol Gen Genet 1975
PMID:The regulatory nature of the phoB gene for alkaline phosphatase synthesis in Escherichia coli. 110 Oct 27

Hybridization of messenger ribonucleic acid (mRNA) isolated from Escherichia Coli K-12 to deoxyribonucleic acid (DNA) from lambdaCI857st68h80dilv was used to detect isoleucine-valine (ilv) specific mRNA. A number of strains partially constitutive for the isoleucine-valine enzymes had levels of ilv mRNA 2 to 3-fold higher than the parent strain. Starvation for any of the branched-chain amino acids resulted in a 20 to 23-fold increase in ilv mRNA as compared to repressed levels. These differences were not due to altered growth rates or to changes in the stability of ilv mRNA. These data indicate that regulation of the isoleucine-valine enzymes by multivalent repression occurs mainly at the level of transcription. Kinetics of elongation of ilv mRNA after repression are consistent with the assumption that the mechanism of multivalent repression involves the prevention of further initiations by RNA polymerase.
Mol Gen Genet 1975 Jun 19
PMID:Transcriptional control of the isoleucine-valine messenger RNA's in E. coli K-12. 110 33


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