Affiliation:
1. Section of Microbiology, The University of California, Davis, Davis, California 95616
Abstract
ABSTRACT
Under conditions of nutrient deprivation,
Myxococcus xanthus
undergoes a developmental process that results in the formation of a fruiting body containing environmentally resistant myxospores. We have shown that myxospores contain two copies of the genome, suggesting that cells must replicate the genome prior to or during development. To further investigate the role of DNA replication in development, a temperature-sensitive
dnaB
mutant, DnaB
A116V
, was isolated from
M. xanthus
. Unlike what happens in
Escherichia coli dnaB
mutants, where DNA replication immediately halts upon a shift to a nonpermissive temperature, growth and DNA replication of the
M. xanthus
mutant ceased after one cell doubling at a nonpermissive temperature, 37°C. We demonstrated that at the nonpermissive temperature the DnaB
A116V
mutant arrested as a population of 1
n
cells, implying that these cells could complete one round of the cell cycle but did not initiate new rounds of DNA replication. In developmental assays, the DnaB
A116V
mutant was unable to develop into fruiting bodies and produced fewer myxospores than the wild type at the nonpermissive temperature. However, the mutant was able to undergo development when it was shifted to a permissive temperature, suggesting that cells had the capacity to undergo DNA replication during development and to allow the formation of myxospores.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference46 articles.
1. Mutants of
Escherichia coli
B/r Defective in Deoxyribonucleic Acid Initiation:
dnaI
, a New Gene for Replication
2. Biswas, E. E., P. H. Chen, and S. B. Biswas. 1994. Structure and function of Escherichia coli DnaB protein: role of the N-terminal domain in helicase activity. Biochemistry 33 : 11307-11314.
3. Biswas, E. E., and S. B. Biswas. 1999. Mechanism of DNA binding by the DnaB helicase of Escherichia coli: structural domains involved in ATP hydrolysis, DNA binding, and oligomerization. Biochemistry 38 : 10919-10928.
4. Biswas, E. E., and S. B. Biswas. 1999. Mechanism of DNA binding by the DnaB helicase of Escherichia coli: analysis of the roles of domain γ in DNA biding. Biochemistry 38 : 10929-10939.
5. Bonhoeffer, F., and H. Schaller. 1965. A method for selective enrichment of mutants based on the high UV sensitivity of DNA containing 5-bromouracil. Biochem. Res. Commun. 109 : 93-97.
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