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D B Willis

Publications and source records attributed to D B Willis.

36 records · Page 2Linked to original sources
PubMed1979

Macromolecular synthesis in cells infected by frog virus 3. XII. Viral regulatory proteins in transcriptional and post-transcriptional controls.

Using fluorophenylalanine (FPA) to interfere with functional viral protein synthesis, we have investigated the complex transcriptional and post-transcriptional controls that operate in cells infected with frog virus 3. Our previous data, obtained by polyacrylamide gel electrophoresis of viral RNAs and proteins, showed that the addition of FPA at the beginning of infection completely prevented the synthesis of late viral RNAs and late viral proteins and blocked the normal progressive decline in the rates of synthesis of two quantitatively different classes (class I and class II) of early proteins. These results indicated that the initiation of late RNA and late protein syntheses, as well as the post-transcriptional regulation of early protein synthesis, was under the control of virus-specific proteins (D. B. Willis, R. Goorha, M. Miles, and A. Granoff, J. Virol. 24:326-342, 1977). In this communication, we show that the viral protein required to "turn on" the synthesis of late RNAs and late (class III) proteins was made within 1 to 1.5 h postinfection (p.i.); when we added FPA after this time, we observed the synthesis of all of the late macromolecules. The data also suggest that another viral protein, separate from the "turn-on" protein, controlled the abundance of late RNAs. In addition, at least two separate proteins were involved in the post-transcriptional regulation of two classes of early proteins. When FPA addition was delayed until 2 h p.i., the rate of synthesis of class I proteins (which normally peaked at 2 h p.i.) was reduced by 6 h p.i. just as in a normal infection, but the rate of synthesis of class II proteins (which normally reached a maximum at 4 h p.i. before declining) was reduced only when we waited until 3 or 4 h p.i. to add FPA. These experiments corroborate and extend previous evidence for the existence of numerous viral regulatory proteins in the control of frog virus 3 gene expression at the transcriptional and post-transcriptional levels.

Animals↗
PubMed1977

Macromolecular synthesis in cells infected by frog virus 3. VI. Frog virus 3 replication is dependent on the cell nucleus.

Previous evidence indicated that frog virus 3 (FV3), an icosahedral DNA virus, replicates exclusively in the cytoplasm. However, data presented here demonstrate that FV3 does not replicate in UV-irradiated or enuleated chicken embryo or BSC-1 cells and that virus-specific DNA synthesis is not initiated in such cells. Primary transcription was not detected in infected enucleated cells. These results demonstrate that a functional nucleus is essential for FV3 replication.

Animals↗
PubMed1977

Macromolecular synthesis in cells infected by frog virus 3. VII. Transcriptional and post-transcriptional regulation of virus gene expression.

We have used improved techniques for separating individual species of RNA and protein to study the mechanisms that control gene expression by frog virus 3, a eucaryotic DNA virus. Forty-seven species of viral RNA and 35 viral polypeptide species were resolved by polyacrylamide gel electrophoresis. The relative molar ratios of virus-specific polypeptides synthesized at various times after infection were determined by computer planimetry and were compared with the molar ratios of appropriate-sized viral RNAs to code for each polypeptide. Viral polypeptides were classified according to the time during the growth cycle at which their maximal rate of synthesis occurred - early, 2 to 2.5 h; intermediate, 4 to 4.5 h; and late, 6 to 6.5 h. The viral RNAs, which were assumed to be mRNA's, could not be classified according to time of maximum synthesis; once their synthesis had begun, most of the RNAs continued to be synthesized at the same or higher rates. However, only 10 of the 47 viral RNA bands were plainly visible after electrophoresis of extracts from cells labeled from 1 to 1.5 h after infection; these 10 RNAs were designated "early" RNA. The early pattern of both RNA and polypeptide synthesis was maintained for at least 6 h in the presence of the amino acid analog fluorophenylalanine, which indicates that a functional viral polypeptide was required for "late" transcription and translation. The presumptive mRNA's for late polypeptides did not appear until 2 h after infection, but two of these "late" RNAs became the major products of transcription by 4 h into the infectious cycle. In contrast to the declining rate of synthesis of the early proteins, corresponding early RNA species continued to be synthesized at the same or higher rates throughout the replicative cycle. Although the synthesis of late virus-specific proteins appeared to be regulated at the level of transcription, our results suggest that the synthesis of both early and intermediate proteins was regulated at the post-transcriptional level.

Animals↗
PubMed1969

Potassium requirement for synthesis of macromolecules in Bacillus subtilis infected with bacteriophage 2C.

A mutant of Bacillus subtilis 168 (strain 168 KW), defective in its ability to concentrate K(+) from low levels in the growth medium, was used to study the role of K(+) in the development of phage 2C. Both the final burst size and the duration of the rise period depended on the K(+) concentration in the medium. During normal infection (in the presence of K(+)), host deoxyribonucleic acid (DNA) synthesis stopped. The synthesis of host messenger ribonucleic acid (RNA) continued throughout infection, albeit at a steadily decreasing rate. The synthesis of ribosomal RNA and its subsequent incorporation into mature ribosomes also proceeded. In contrast to these findings, host DNA and messenger RNA synthesis were not inhibited in cells infected in the absence of K(+). Only "early" phage messenger RNA was synthesized under these conditions of infection. Phage DNA synthesis was dependent on K(+) irrespective of the requirement for this cation in protein synthesis.

Bacillus subtilis↗
PubMed1968

Ribonucleic acid and protein synthesis in a mutant of Bacillus subtilis defective in potassium retention.

A mutant of Bacillus subtilis 168 (strain 168 KL), which had lost its normal capacity to accumulate K(+), was used to explore the interrelationship between protein and ribonucleic acid (RNA) synthesis. In contrast to the wild type, the growth rate of strain 168 KL was markedly dependent on the K(+) concentration in the medium. K(+) uptake in the mutant strain was identical to that in the parent, but the mutant was unable to retain and accumulate K(+). Protein synthesis was markedly dependent on the K(+) concentration in the medium, whereas RNA synthesis was relatively unaffected by changes in the level of K(+). Most of the RNA synthesized during K(+) depletion was ribosomal RNA; it appeared in crude extracts in the form of ribonucleoproteins particles with sedimentation values between 4S and 30S. These particles were converted into mature ribosomes when growth was allowed to resume by the addition of K(+). Simultaneous synthesis of RNA and protein was necessary for the quantitative conversion of the ribonucleoprotein particles into ribosomes. During recovery from K(+) depletion, ribosomal protein was synthesized in preference to the other proteins of the cell.

Bacillus subtilis↗
PubMedDate not supplied

Transcription of methylated viral DNA by eukaryotic RNA polymerase II.

The genome of the large icosahedral DNA virus, frog virus 3 (FV3), is heavily methylated at the cytosine residues of dCdG dinucleotide pairs, with more than 22% of the total cytosine residues in the form of 5-methylcytosine (5mC). This methylation is carried out postreplicatively in the cytoplasm of infected cells by a virus-encoded DNA methyltransferase. DNA methyltransferase activity was shown to copurify with a 26 kD virus-induced, DNA-binding protein that had an altered mobility in extracts from cells infected with a DNA-methyl-transferase deficient mutant of FV3. Immediately after infection, the highly methylated parental DNA is transcribed in the nucleus by the host cell RNA polymerase II. As FV3 induces the synthesis of a protein that can override the inhibitory effect of methylation on the transcription of exogenous promoters methylation in vitro, we suggest that this protein is a factor evolved by this virus to allow transcription from methylated promoters by eukaryotic RNA polymerase II.

Animals↗
PubMedDate not supplied

Evaluation of the American Cancer Society's Research Promotion Guide.

The American Cancer Society has supported cancer research for more than 50 years and has devoted more than $2.2 billion to cancer research. This article describes an evaluation of the Research Promotion Guide of the American Cancer Society, a reference tool developed by the National Home Office for regional division staff and volunteers whose work involved public relations and fundraising. The purposes of this study were the following: 1) to determine the level and type of use of the guide; and 2) to assess factors that may influence the level and type of use. Fifty-five participants were interviewed by telephone. Overall, 78% of them were aware of the guide. Three factors significantly and positively associated with level of use were: compatibility (the perception that the guide is relevant to one's job); attending a training session; and years employed at the American Cancer Society. This study, a pilot project for the Collaborative Evaluation Fellows Project (CEFP), demonstrated that collaboration between nonprofit and academic institutions is feasible and can serve the needs of the students and organizations. The lessons learned can be applied to evaluations in general and to future CEFP projects.

Humans↗