Bacterial Nucleoid Occlusion Proteins

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The primary purpose of this research article was to discuss the many ways bacterial nucleoid could be regulated during the cell cycle. The article focused itself on FtsZ and its role in Z ring formation and nucleoid occlusion proteins in two types of bacteria, B. Subtilis and E. Coli. The majority of a bacterial cell is made up of chromosomes which are housed in the nucleoid. Thus, in order to maintain the genetic material chromosomal replication and segregation must be coordinated with cell division. One way is through the use of nucleoid occlusion factors which protect the DNA by preventing Z ring assembly over it. Most bacteria divide via binary fission which is initiated by the formation of a Z-ring structure at the division site. …show more content…
It does this by having MinD recruit MinC which inhibits FtsZ from forming the ring. The MinCD complex in E. coli oscillates back and forth to both ends of the pole and in B. Subtilis the MinCD complex is recruited to both cell poles. Overall it generates the same net affect which is bringing the MinCD complex to both poles and preventing Z ring assembly …show more content…
The activated complex then works to inhibit FtsZ polymerization and thereby preventing cell division. Noc, on the other hand, associates with the cell membrane which is controlled by NBSs.

The shape of the cell also plays a role in how regulation occurs. In coccus or spherical shaped bacteria, the chromosome occupies most of the cytoplasm. As a result, nucleoid occlusion proteins play a very important role, particularly because most coccus shaped bacteria don’t have the Min system. If the Noc is deleted then about 15% of the cells have septum formation and cell division over the nucleoid.

The researchers also looked at how B. Subtilis and E. Coli react when they lack both the Min system and nucleoid occlusion proteins. They found that the FtsZ still doesn’t form where genome is present and thus concluded that there must be other factors that select the division site.

To conclude, the researchers made an important discovery with the identification of Noc and SlmA and the role they play in cell division. However, there are still many questions that need to be resolved, including how nucleoid occlusion factors change with growth rate and with different types of

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