A rapid nuclear isolation technique was adapted in
order to examine the question of DNA precursor
compartmentation in mammalian cells. By using this method
a reproducible proportion of the cellular nucleotides
remained associated with the isolated nuclei.
Examination, at several different cell densities, of
exponentially growing HeLa cells showed that...
The activity of deoxyribose-phosphate aldolase was determined
in chick embryo brains, hearts and livers during the course of development.
Assays were made in the direction of synthesis of deoxyribose-5-phosphate. Low levels of activity in the brain and heart
remained constant throughout the course of development. Activity in
the liver expressed...
Bacteriophage T4 gene 42 encodes dCMP hydroxymethylase, an
enzyme unique to the deoxyribonucleotide metabolism of T-even
bacteriophages. To study biochemical and biophysical properties of
the enzyme, as well as the interaction of dCMP hydroxymethylase with
other DNA precursor biosynthetic enzymes in vitro, availability of large
amounts of the enzyme is...
Imbalanced deoxyribonucleoside triphosphate (dNTP) pools are mutagenic for DNA synthesis in both intact cells and cell-free replication systems. Almost certainly, such mutagenesis involves competition between correctly and incorrectly base-paired precursors at replication sites. However, there are certain differences between the intact cell and cell-free systems that do not always allow...
Vaccinia virus-infected animal cells have been used to
study the interactions between the replication of
deoxyribonucleic acid (DNA) and the biosynthesis of its
nucleotide precursors. Some antimetabolites that inhibit
DNA replication have as their targets enzymes of nucleotide
biosynthesis. Furthermore, the disruption of nucleotide
metabolism can alter the fidelity of...
The work in this thesis has provided conclusive genetic evidence
that "panhandle" intermediates form during adenovirus replication.
Adenovirus chromosomes lacking 51 by from their left -hand termini
are infectious and capable of regenerating the missing origin
sequence. Yet if an entire inverted terminal repeat is removed, the
adenovirus chromosome is...
Deoxyribonucleoside triphosphate (dNTP) concentrations measured in cells are not symmetric. dGTP almost always represents only 5-10% of the total dNTP pools in cells. In an in vitro replication system involving semiconservative replication from an SV 40 origin, the mutation frequency of an M13 phagemid replicated by human cell extracts in...
Although the synthesis of DNA precursors is
closely coordinated with DNA replication, it is still
not clear whether deoxyribonucleoside triphosphates
(dNTPs) influence DNA replication independently of
their interactions with DNA polymerase catalytic sites.
In an effort to understand the extent to which rate and
fidelity of DNA replication are regulated...
A crucial factor in determining the accuracy of DNA replication is
maintenance of a balanced supply of deoxyribonucleoside triphosphates
(dNTPs) at replication forks. Perturbation of dNTP biosynthesis can
induce dNTP pool imbalance with deleterious genetic consequences,
including increased mutagenesis, recombination, chromosomal
abnormalities and cell death. Using the T4 bacteriophage system,...