Parameters of unbalanced growth and reversible inhibition of deoxyribonucleic acid synthesis in Brevibacterium ammoniagenes ATCC 6872 induced by depletion of Mn2+. Inhibitor studies on the reversibility of deoxyribonucleic acid synthesis

The sensitivity of phage T 7 to epoxides and freshly prepared solutions of di(2-chloroethyl) methylamine ( HN 2) was identical with that of T 2. T 7, however, proved considerably the more sensitive to ethylenimine and to aged solutions of HN 2. It was considered that this was due to the cationic nature of these latter agents affecting the rate of penetration into the phage heads, and that the susceptibility of T 2 and resistance of T 7 to osmotic shock was a parallel phenomenon. Confirmation was afforded by the fact that a strain of T 4 sensitive to osmotic shock behaved like T 2, and a resistant strain of T 4 like T 7. These results, together with others previously reported, are believed to offer very strong evidence that inactivation of bacteriophage by alkylating agents derives from reaction with the deoxyribonucleic acid moiety, probably leading to a failure of the injection process.

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Induction of cellular deoxyribonucleic acid synthesis in butyrate-treated cells by simian virus 40 deoxyribonucleic acid

Molecular and Cellular Biology ◽

10.1128/mcb.1.11.1038-1047.1981 ◽

1981 ◽

Vol 1 (11) ◽

pp. 1038-1047

Author(s):

S Kawasaki ◽

L Diamond ◽

R Baserga

Keyword(s):

Ribonucleic Acid ◽

Deoxyribonucleic Acid ◽

Simian Virus 40 ◽

Acid Synthesis ◽

Simian Virus ◽

S Phase ◽

Temperature Sensitive ◽

3T3 Cells ◽

Deoxyribonucleic Acid Synthesis ◽

G1 Cells

Sodium butyrate (3 mM) inhibited the entry into the S phase of quiescent 3T3 cells stimulated by serum, but had no effect on the accumulation of cellular ribonucleic acid. Simian virus 40 infection or manual microinjection of cloned fragments from the simian virus 40 A gene caused quiescent 3T3 cells to enter the S phase even in the presence of butyrate. NGI cells, a line of 3T3 cells transformed by simian virus 40, grew vigorously in 3 mM butyrate. Homokaryons were formed between G1 and S-phase 3T3 cells, Butyrate inhibited the induction of deoxyribonucleic acid synthesis that usually occurs in B1 nuclei when G1 cells are fused with S-phase cells. However, when G1 3T3 cells were fused with exponentially growing NGI cells, the 3T3 nuclei were induced to enter deoxyribonucleic acid synthesis. In tsAF8 cells, a ribonucleic acid polymerase II mutant that stops in the G1 phase of the cell cycle, no temporal sequence was demonstrated between the butyrate block and the temperature-sensitive block. These results confirm previous reports that certain virally coded proteins can induce cell deoxyribonucleic acid synthesis in the absence of cellular functions that are required by serum-stimulated cells. Our interpretation of these data is that butyrate inhibited cell growth by inhibiting the expression of genes required for the G0 leads to G1 leads to S transition and that the product of the simian virus 40 A gene overrode this inhibition by providing all of the necessary functions for the entry into the S phase.

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