Effect of chloramphenicol and starvation for an essential amino acid on the synthesis and decay of T4 bacteriophage-specific messengers transcribed from early and quasi-late promoters

Baros, Anna; Witmer, H

doi:10.1016/0003-9861(75)90183-6

Cited by 8 publications

(6 citation statements)

References 28 publications

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“…10). These results confirm previous conclusions based upon indirect methods of mRNA detection (2,36,41,46).…”

Section: Discussionsupporting

confidence: 92%

“…This suggests that production of the two mRNA species is turned off by the same mechanism. The HMase gene is transcribed exclusively from a type ofpromoter that starts to function moments after infection (2,17), i.e., an early promoter (44). The kinase gene, on the other hand, is transcribed exclusively from a special kind of prereplicative promoter, termed quasi-late (40,44), that does not start to function until 1.5 to 2 min after infection (2, 17).…”

Section: Discussionmentioning

confidence: 99%

“…The preinfection addition of chloramphenicol selectively inhibits accumulation of many T4 phage prereplicative messengers (1,2,4,11,25,36,46,50,51,62;Witmer et al,in press). HMase mRNA did accumulate under such conditions but at a subnormal rate (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Control of synthesis of mRNA's for T4 bacteriophage-specific dihydrofolate reductase and deoxycytidylate hydroxymethylase

Witmer¹,

Baros²,

Ende³

et al. 1976

J Virol

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A 300C, functional messengers for dCMP hydroxymethylase first appeared 3 to 6 min postinfection and reached their maximum levels at 12 min. Chloramphenicol, added before the phage, reduced the rate of mRNA accumulation. When the antibiotic was added 6 min postinfection, mRNA levels increased at their normal rate but there was no obvious repression of messenger accumulation. Delaying the addition of drug until 8 or 12 min had progressively less effect on the pattern of hydroxymethylase mRNA metabolism. When chloramphenicol was present from preinfection times or from 6 min postinfection, all hydroxymethylase mRNA's synthesized were stable; at later times, however, the ability of the drug to stabilize mRNA decreased with its ability to delay the turnoff of mRNA production. An overaccumulation of hydroxymethylase mRNA was also seen when phage-specific DNA synthesis was inhibited either by mutational lesion in an essential viral gene or by 5-fluorodeoxyuridine. By min 20 of a DNA-negative program, hydroxymethylase mRNA synthesis was repressed to the point where it no longer compensated for decay. However, a finite level of hydroxymethylase mRNA synthesis was maintained at later times of a DNA-negative infection. Such results indicate that replication of the phage chromosome is necessary but not sufficient for a complete turnoff of hydroxymethylase mRNA production. Functions controlled by the maturation-defective proteins (the products of genes 55 and 33) played only a minor role in the regulation of hydroxymethylase mRNA metabolism. Thus, we favor the hypothesis that a complete turnoff of hydroxymethylase messenger production requires one or more new proteins as well as an interval of DNA replication. The absence of DNA synthesis had no particular effect upon dihydrofolate reductase messenger production. The preinfection addition of chloramphenicol likewise had little effect on dihydrofolate reductase messenger metabolism. These latter data imply that prior synthesis of a phage-coded protein synthesis may not be required for the turnoff of reductase messenger production.

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“…10). These results confirm previous conclusions based upon indirect methods of mRNA detection (2,36,41,46).…”

Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

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Control of synthesis of mRNA's for T4 bacteriophage-specific dihydrofolate reductase and deoxycytidylate hydroxymethylase

Witmer¹,

Baros²,

Ende³

et al. 1976

J Virol

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“…This value is quite approximate, however, because in the experiment of Fig. 9 the labeling interval began at 5 min after infection, by which time considerable early enzyme synthesis has occurred (1,26). Additional experiments involving increased specific activities, isotopes of higher energy, and extended labeling intervals are under way.…”

Section: Mixturementioning

confidence: 87%

“…To answer both questions we labeled E. coli for one generation of g p 9 growth and then infected it in nonradioactive medium with either T4 amB272 (gene 23) or T4 amE10 (gene 45). Tail-containing fractions 9 p 1 from the 23-infection and corresponding fractions from the 45-infection were analyzed electrophoretically ( Fig. 7).…”

Section: 8mentioning

confidence: 99%

Bacteriophage T4 Virion Dihydrofolate Reductase: Approaches to Quantitation and Assessment of Function

Mosher

DiRenzo

Mathews

1977

J Virol

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This paper is concerned with the physiological role(s) of T4 phage-coded dihydrofolate reductase, which functions both in DNA precursor metabolism and as a virion protein. (i) We have detected enzyme activity in noninfectious particles produced under restrictive conditions by gene 11 mutants. This supports the conclusion of Kozloff et al. (J. Virol. 16:1401-1408, 1975) that the protein lies in the baseplate, covered by the gene 11 protein. (ii) We have obtained further evidence for virion dihydrofolate reductase as the target for neutralizing activity of T4 dihydrofolate reductase antiserum and as a determinant ofthe heat lability of the virion. This derives from our observation that the reductases specified by T4B and T4D differ in several properties. (iii) We have investigated several anomalous properties of T4 mutants bearing deletions that reportedly extend into or through the frd gene, which codes for dihydrofolate reductase. Evidence is presented that the deletions in fact do not extend through frd. These strains direct the synthesis of material that cross-reacts with antiserum to homogeneous dihydrofolate reductase. Moreover, they are all quite sensitive to the phage-neutralizing effects of this antiserum. In addition, they are restricted by several of the hospital strains, wild-type strains ofEscherichia coli supplied by the California Institute of Technology group. (iv) We have attempted to detect dihydrofolate reductase among early-synthesized proteins present in T4 tails. Two such proteins are seen, one of which is evidently the gene 25 product and one that is a bacterial protein. Quantitation of our electrophoretic technique has allowed determination of the number of molecules of some T4 tail components present per virion. (v) Finally, we have compared the T4 dihydrofolate reductase with the corresponding enzyme specified by two plasmids conferring resistance to trimethoprim (Skold and Widh, J. Biol. Chem. 249:4324-4325, 1974). Although the enzymes are similar in some properties, they differ in several important respects, including immunological activity.

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Synthesis of 5-hydroxymethyldeoxyuridine triphosphate in extracts of SP10c phage-infectedBacillus subtilis W23

Witmer

Dosmar

1978

Current Microbiology

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Effect of chloramphenicol and starvation for an essential amino acid on the synthesis and decay of T4 bacteriophage-specific messengers transcribed from early and quasi-late promoters

Cited by 8 publications

References 28 publications

Control of synthesis of mRNA's for T4 bacteriophage-specific dihydrofolate reductase and deoxycytidylate hydroxymethylase

Control of synthesis of mRNA's for T4 bacteriophage-specific dihydrofolate reductase and deoxycytidylate hydroxymethylase

Bacteriophage T4 Virion Dihydrofolate Reductase: Approaches to Quantitation and Assessment of Function

Synthesis of 5-hydroxymethyldeoxyuridine triphosphate in extracts of SP10c phage-infectedBacillus subtilis W23

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