Dps Is a Stationary Phase-Specific Protein of Escherichia coli Nucleoid

Ali Azam Talukder^1,2,3,4,5*, Akira Ishihama^2,3

¹Department of Microbiology, Jahangirnagar University, Savar, Bangladesh.
²Department of Molecular Genetics, National Institute of Genetics, Mishima, Japan.
³Micro-Nano Technology Research Center, Hosei University, Tokyo, Japan.
⁴Japan Science and Technology Corporation, Kawaguchi, Japan.
⁵Japan Society for the Promotion of Science, Tokyo, Japan.

DOI: 10.4236/aim.2014.415120                

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.

Keywords

Dps, DNA-Binding Protein, Stationary Phase, E. coli, Nucleoid

Conflicts of Interest

The authors declare no conflicts of interest.

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