Effect of the relA gene on the synthesis of individual proteins in vivo

Furano, Anthony V.; Wittel, Frederick P.

doi:10.1016/0092-8674(76)90192-6

Cited by 33 publications

(14 citation statements)

References 23 publications

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“…It has been shown in vivo that when a stringent strain of E. coli is starved for an amino acid, the syntheses of ribosomal proteins and various elongation factors are depressed (24)(25)(26). This inhibition is thought to be mediated by the nucleotide ppGpp, which accumulates during starvation.…”

Section: Discussionmentioning

confidence: 99%

“…Little is known about the regulation of the synthesis of these proteins. The synthesis of L12 and EF-Tu is under stringent control, because both proteins (as well as ribosomal RNA and other ribosomal proteins) are decreased during amino acid starvation in a stringent but not in a relaxed organism (24)(25)(26). Guanosine 5'-diphosphate 3'-diphosphate (ppGpp), a nucleotide that accumulates in a stringent organism during amino acid starvation (27), is thought to mediate the decrease in the synthesis of L12 and EF-Tu.…”

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confidence: 99%

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mRNA-dependent in vitro synthesis of ribosomal proteins L12 and L10 and elongation factor Tu.

Chu¹,

Caldwell²,

Weissbach³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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RNA extracted from growing Escherichia coli can direct the in vitro synthesis of ribosomal proteins L12 and L1O and elongation factor Tu when an E. coli system is used. The synthesized L12 can be bound to L12-depleted ribosomes and the synthesized elongation factor Tu can form complexes with both elongation factor Ts and GDP. Guanosine 5'-diphosphate 3'.diphosphate has no effect on the synthesis of these proteins from an RNA template but inhibits their synthesis when a DNA template is used.Specialized transducing phages containing different clusters of bacterial genes in conjunction with DNA-directed-cell-free protein synthesis systems have proven to be useful tools for studying the synthesis and regulation of specific proteins in bacteria (1-7). Although RNA phages have been used as templates to study the in vitro synthesis of various phage proteins (reviewed in ref. 8), the use of bacterial mRNA has been limited. It has been shown that mRNA extracted from Escherichia coli as well as mRNA obtained from the in vitro transcription of transducing phage DNA can direct the in vitro synthesis of several E. coli proteins and peptides, including an outer membrane lipoprotein (9), alkaline phosphatase (10), gene products of the galactose operon (11), and the NH2-terminal portions of tryptophanase (12) and ,B-galactosidase (13).It is known that E. coli ribosomal protein L12* and elongation factor (EF) Tu are produced in large amounts relative to other proteins. Multiple copies of L12 are present on the ribosome (14-18) in addition to the amount of L12 found in the postribosomal supernatant (19)(20)(21). It has been shown that there are two genes coding for and that this protein may constitute >5% of the soluble protein of E. coli (23). Little is known about the regulation of the synthesis of these proteins. The synthesis of L12 and EF-Tu is under stringent control, because both proteins (as well as ribosomal RNA and other ribosomal proteins) are decreased during amino acid starvation in a stringent but not in a relaxed organism (24-26). Guanosine 5'-diphosphate 3'-diphosphate (ppGpp), a nucleotide that accumulates in a stringent organism during amino acid starvation (27), is thought to mediate the decrease in the synthesis of L12 and EF-Tu. Recent studies (28, 29) using DNA from the transducing phage Xrifdl8 (which contains genes for EF-Tu, L10, and L12) as template for the in vitro synthesis of both L12 and EF-Tu have corroborated the in vivo results in that the DNA-directed cell-free synthesis of both proteins was inhibited by ppGpp. Indirect evidence suggested that the inhibition by ppGpp was at the level of transcription (29).The present communication describes the preparation of an E. coli RNA fraction capable of directing the in vitro synthesis of ribosomal proteins L10 and L12 and EF-Tu. As opposed to the DNA-directed synthesis of these proteins (28-30), the RNA-directed synthesis of these proteins is unaffected by ppGpp. (34), using 3H-labeled formaldehyde (New England Nuclear Corp.). Ribosomal wash, wa...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mRNA-dependent in vitro synthesis of ribosomal proteins L12 and L10 and elongation factor Tu.

Chu¹,

Caldwell²,

Weissbach³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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“…Evidence for such a view has appeared for prokaryotic cells as well (Krauss & Leder, 1975;Furano, 1975;Furano & Wittel, 1976). Although variations in mRNA concentration and initiationfactor activity appear to be important for the regulation of translation [for a review see Lodish (1976)], there is a growing body of evidence to support the view that elongation factors may also be involved in regulation (see, for example, Nicholls et al, , 1975Smith et al, 1976;Haschemeyer & Persell, 1973).…”

Section: Discussionmentioning

confidence: 99%

Regeneration of renal proximal tubules after mercuric chloride injury is accompanied by increased binding of aminoacyl-transfer ribonucleic acid

McEwen

1976

Biochemical Journal

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Homogenates of rat kidney cortex obtained 1,3 or 14 days after a single injection of HgCl2 were used to prepare the post-microsomal pH5 supernatant fraction. The activity of this fraction for peptide synthesis from [14C]phenylalanyl-tRNA was significantly increased at 1 and 3 days, at which time the proximal tubules are regenerating [Cuppage & Tate (1967) Am. J. Pathol. 51, 405-429]. This increased activity could not be attributed to a decreased inhibitory activity, but was due to an increased aminoacyl-tRNA binding, i.e. elongation-factor-1 activity, in the supernatant fraction.

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“…RNA was isolated from cells by the method of Furano and Witell (11). RNA (20 g) was separated by electrophoresis on a 1% agarose gel and then transferred to a nylon filter (Hybond-N; Amersham) by the method of Sambrook et al (40).…”

Section: Methodsmentioning

confidence: 99%

Na+-induced transcription of nhaA, which encodes an Na+/H+ antiporter in Escherichia coli, is positively regulated by nhaR and affected by hns

et al. 1996

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nhaA encodes an Na+/H+ antiporter in Escherichia coli which is essential for adaptation to high salinity and alkaline pH in the presence of Na+. We used Northern (RNA) analysis to measure directly the cellular levels of nhaA mRNA. NhaR belongs to the LysR family of regulatory proteins. Consistent with our previous data with an nhaA'-'lacZ fusion, NhaR was found to be a positive regulator and Na+ was found to be a specific inducer of nhaA transcription. In the nhaA'-'lacZ fusion, maximal induction was observed at alkaline pH. In contrast, in the nhaA+ strain both the level of nhaA expression and the induction ratio were lower at alkaline pH. This difference may be due to the activity of NhaA in the wild-type strain as NhaA efficiently excreted Na+ at alkaline pH and reduced the intracellular concentration of Na+, the signal for induction. We also showed that although the global regulator rpoS was not involved in nhaA regulation, the global regulator hns played a role. Thus, the expression of nhaA'-'lacZ was derepressed in strains bearing hns mutations and transformation with a low-copy-number plasmid carrying hns repressed expression and restored Na+ induction. The derepression in hns strains was nhaR independent. Most interestingly, multicopy nhaR, which in an hns+ background acted only as an Na+-dependent positive regulator, acted as a repressor in an hns strain in the absence of Na+ but was activated in the presence of the ion. Hence, an interplay between nhaR and hns in the regulation of nhaA was suggested.

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Effect of the relA gene on the synthesis of individual proteins in vivo

Cited by 33 publications

References 23 publications

mRNA-dependent in vitro synthesis of ribosomal proteins L12 and L10 and elongation factor Tu.

mRNA-dependent in vitro synthesis of ribosomal proteins L12 and L10 and elongation factor Tu.

Regeneration of renal proximal tubules after mercuric chloride injury is accompanied by increased binding of aminoacyl-transfer ribonucleic acid

Na+-induced transcription of nhaA, which encodes an Na+/H+ antiporter in Escherichia coli, is positively regulated by nhaR and affected by hns

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