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Biomedical subjects

R W Moyer

Publications and source records attributed to R W Moyer.

90 records · Page 5Linked to original sources
PubMed1980

The white pock (mu) mutants of rabbit poxvirus. III. Terminal DNA sequence duplication and transposition in rabbit poxvirus.

The restriction fragment patterns of the DNA of three white pock (mu) nonhost range mutants RPmu mutants) of rabbit poxvirus (RPV) show the presence of net insertions of DNA. Two of the mutants (RPmu21 and RPmu7) contain two molar quantities of 13 X 10(6) and 15 X 10(6) daltons, respectively, of the left-most viral DNA sequences. The extra copy of these sequences was inserted into the right-most region of the viral genome which in both cases had been modified by deletion of 10 X 10(6) daltons of the original extreme right-most DNA sequences. Hence two mutants with "left-hand" mirror image termini of 13 X 10(6) and 15 X 10(6) daltons of DNA were generated with an overall net increase in mass of 3 X 10(6) and 5 X 10(6) daltons of DNA to yield genome molecular weights of 121 X 10(6) and 123 X 10(6) for RPmu21 and 7, respectively. A third mutant (RPmu81g) contained 28 X 10(6) daltons of the right-most parental DNA sequences inserted into the left end of the genome, which had deleted 6 X 10(6) daltons of the extreme left-hand sequences. This variant contains "right-hand" mirror image termini of 28 X 10(6) daltons of DNA and a net increase in molecular weight of 22 X 10(6) daltons of DNA to yield a genome molecular weight of 140 X 10(6). The cross-linked end of the transposed sequences is retained in all cases. Our data suggest that the terminal DNA sequences at either end of the virus are not essential for a productive infection in certain host cells and that the pathogenicity of orthopoxviruses may be related in part to a series of varied and interchangeable DNA sequences located at both extremes of a high conserved genome core.

Base Sequence↗
PubMed1980

Characterization of the non-permissive infection of rabbit cornea cells by vesicular stomatitis virus.

Rabbit cornea cells (RC-60) restrict the reproduction of vesicular stomatitis virus (VSV) (Thacore & Youngner, 1975). In cells infected with VSV alone, an inhibition in the synthesis of VSV genome RNA is observed. A number of parameters which could affect virus RNA synthesis have been examined: virus transcription and post-transcriptional modification, translation, modification of proteins and migration of the G protein to the surface of the cell; they all appear to be normal, although somewhat diminished, in the restricted system. In these cells, therefore, it is the replication of VSV RNA that is directly inhibited, although limited synthesis of both (+) and (-) strand genome length RNA does occur. When the cells are co-infected with rabbit poxvirus (RPV) as a helper virus, however, VSV production is normal. Our studies suggest that RPV plays a role in the maturation as well as in the replication of VSV RNA in RC-60 cells. Certain mutants of RPV have been found to lack the helper function and are unable to convert the RC-60 cells into a permissive host for VSV. These mutants should facilitate the elucidation of the mechanism by which RPV is able to overcome the restriction in these cells.

Animals↗
PubMed1979

The purification and properties of a double-stranded DNA-binding protein encoded by the gene D5 of bacteriophage T5.

We have purified a DNA-binding protein from bacteriophage T5-infected cells. The protein is the product of the T5 gene D5 and is produced in quantities ultimately exceeding 2% of the total cell protein. The protein has no tendency to aggregate and exists in solution as a monomer of about 29,000 daltons. Although the protein binds with a high affinity to both single-stranded (fd, T7) and duplex DNA (T5, T7), there is a preferred binding to duplex DNA. The binding of the gene D5 protein to duplex DNA is cooperative with an estimated dissociation constant of 6.27 x 10(-10) M and leads to the production of a more condensed form of the DNA. In contrast, binding of the gene D5 protein to single-stranded DNA is noncooperative with an estimated dissociation constant of only 1.85 x 10(-8) M and produces a sedimentation shift in the DNA proportional to the added mass of the protein. The protein product of the gene D5 of bacteriophage T5 is known to be required for both T5 DNA replication and for the inhibition of early phage gene expression. We also show here that the protein is required to initiate transcription of the late region of the T5 genome.

Amino Acids↗
PubMed1979

Gene D5 product of bacteriophage T5: DNA-binding protein affecting DNA replication and late gene expression.

Gene D5 is not only necessary for replication of bacteriophage T5 DNA and for shutoff of expression of some early genes, but has been found to be necessary also for the expression of late T5 genes. The polypeptide product of gene D5 has been identified, an intragenic map of gene D5 has been constructed, and the direction of transcription of gene D5 has been established. The polypeptide coded by gene D5 has been shown to be a DNA-binding protein with affinity for both double- and single-stranded DNA.

Coliphages↗
PubMed1977

Role of the T5 gene D15 nuclease in the generation of nicked bacteriophage T5 DNA.

The processing of newly replicated concatameric T5 DNA into both single stranded DNA changed of unit length and single-stranded fragments of sizes comparable to those found in mature T5 virion DNA occurs in the absence of late T5 protein synthesis. The formation of unit-length, single-stranded DNA chains does not require the early T5 gene D15 nuclease: however, the subsequent formation of the single-stranded fragments does require that the D15 nuclease be functional. A reexamination of the properties of the purified D15 nuclease under a variety of conditions showed that, in addition to functioning as a 5' leads to 3' exonuclease, the enzyme can also introduce endonucleolytic scissions into mature T5 DNA in a reaction that requires duplex T5 DNA and preexisting, single-stranded interruptions.

Coliphages↗
PubMed1975

The regulation of transcription in bacteriophage T5-infected Escherichia coli.

The expression of bacteriophage T5-specific RNA and protein in infected cells is temporally separated into three classes: class I (preearly), class II (early), and class III (late). By immunoprecipitation techniques we have shown that T5 infection of cells leads to the synthesis of one class I polypeptide (11,000 daltons) and two class II polypeptides (90,000 and 15,000 daltons) capable of binding to the RNA polymerase of the host Escherichia coli cell. One of the class II polypeptides (90,000 daltons) is the product of gene C2, which is an essential gene product required for the initiation of class III RNA synthesis. The colicinogenic factor, ColIb, is a plasmid which prevents the normal synthesis of class II and the III bacteriophage T5-specific RNA in infected colicinogenic (ColIb+) cells. In T5-infected colicinogenic cells, only the T5 class I polypeptide is found associated with the RNA polymerase. Mutants of T5, designated T5h minus, are capable of growth on both noncolicinogenic and ColIb+ hosts. Extracts of T5h minus infected ColIb+ cells were shown to lack a small class I polypeptide (12,000 daltons) as compared to T5-infected cells. The h minus mutation, however, has no effect on the levels of the class I T5 polypeptide of similar molecular weight which is bound to the RNA polymerase. One effect of the h minus mutation is to enhance the quantities of the two class II polypeptides bound to the enzyme.

Bacterial Proteins↗
PubMed1975

Purification and properties of a bacteriophage T5-modified form of Escherichia coli RNA polymerase.

A modified form of Escherichia coli RNA polymerase that contains one of the three T5-specific polypeptides known to interact with the host enzyme was purified from bacteriophage T5-infected cells. The properties of this T5-modified enzyme appeared identical to those of the RNA polymerase derived from uninfected non-colicinogenic cells and to a fully active enzyme isolated from T5-infected ColIb+ cells after the limited in vivo transcription of T5 genes allowed by the plasmid had ceased.

Coliphages↗
PubMed1974

In vivo repair of the single-strand interruptions contained in bacteriophage T5 DNA.

Bacteriophage T5 is known to contain several unique single-strand interruptions in only one strand of the duplex DNA. Analysis of labeled parental phage DNA from infected Escherichia coli shows that these nicks are repaired in vivo to yield intact double-stranded molecules. Sealing begins at about 6 min after infection and is independent of DNA replication. Repair may be an ordered process that starts at a unique end of the molecule.

Autoradiography↗
PubMed1972

Regulation of bacteriophage T5 development by ColI factors.

The I-type colicinogenic factor ColIb transforms Escherichia coli from a permissive to a nonpermissive host for bacteriophage T5 reproduction by preventing complete expression of the phage genome. T5-infected ColIb(+) cells synthesize only class I (early) phage protein and ribonucleic acid (RNA). Neither phage-specific class II proteins [associated with viral deoxyribonucleic acid (DNA) replication] nor class III proteins (phage structural components) are formed due to the failure of the infected ColIb(+) cells to synthesize class II or class III phage-specific messenger RNA. Comparable studies with T5-infected cells colicinogenic for the related ColIa factor revealed no decrease in the yield of progeny phage although the presence of the ColIa factor leads to a significant reduction in the amount of phage-directed class III protein synthesis.

Adenine↗
PubMed1969

Patterns of RNA synthesis in T5-infected cells. I. As studied by the technique of DNA-RNA hybridization-competition.

The RNA-labeling patterns obtained after T5 infection of Escherichia coli F agree with the patterns of protein labeling published by McCorquodale and Buchanan.(1) Three distinct classes of RNA formed sequentially during the period of viral development can be recognized by the DNA-RNA hybridization-competition technique. Class I RNA is formed within 5 minutes after the beginning of viral metabolism and corresponds to the RNA synthesized in response to infection with the 8 per cent segment of T5 DNA. Protein synthesis directed by this 8 per cent segment is required in some capacity for the cessation of class I synthesis and the beginning of the synthesis of class II at 4 to 5 min after infection. Class III RNA synthesis begins between 9 and 12 minutes. Its appearance is prevented when chloramphenicol is added immediately after complete expression of class I functions.

Bacterial Proteins↗