TITLE:
Dps Is a Stationary Phase-Specific Protein of Escherichia coli Nucleoid
AUTHORS:
Ali Azam Talukder, Akira Ishihama
KEYWORDS:
Dps, DNA-Binding Protein, Stationary Phase, E. coli, Nucleoid
JOURNAL NAME:
Advances in Microbiology,
Vol.4 No.15,
November
24,
2014
ABSTRACT: Bacterial genomic DNA is highly organized
into one or few compacted bodies known as nucleoid, which is composed of DNA,
RNA and several DNA-binding proteins. These DNA-binding proteins require
essential alterations in their expression during stationary phase of growth in
order to re-spond to stressful environmental conditions. Dps (DNA-binding
protein from starved cells) is one of such DNA-binding proteins, which
accumulates most when E. coli cells reach to the stationary phase. Here, we
have characterized Dps protein under various growth phases. Immunofluorescent
microscopic observation reveals that Dps plays a key role in final round of
genome compaction during the stationary phase. Similar results are also
obtained by Western immunoblot analysis, after quantification of Dps protein
from the exponential phase and early stationary phase nucleoid bound fractions,
separated by sucrose density gradient centrifugation. Our results support the
conclusion that Dps occupies more than half of the stationary phase nucleoid in E. coli.