Inclusion bodies

It has been suggested that inclusion bodies are dynamic structures formed by an unbalanced equilibrium between aggregated and soluble proteins of Escherichia coli.

This is often true when large evolutionary distances are crossed: a cDNA isolated from Eukarya for example, and expressed as a recombinant gene in a prokaryote risks the formation of the inactive aggregates of protein known as inclusion bodies.

While the cDNA may properly code for a translatable mRNA, the protein that results will emerge in a foreign microenvironment.

For example, eukaryotic systems for carbohydrate modification and membrane transport are not found in prokaryotes.

The internal microenvironment of a prokaryotic cell (pH, osmolarity) may differ from that of the original source of the gene.

[citation needed] Inclusion bodies are aggregates of protein associated with many neurodegenerative diseases, accumulated in the cytoplasm or nucleus of neurons.

Polymeric R bodies are found in the bacterial cytoplasm of some taxa, and thought to be involved in toxin delivery.

Solubilisation of inclusions bodies often involves treatment with denaturing agents, such as urea or guanidine chloride at high concentrations, to de-aggregate the collapsed proteins.

Although, the renaturation of inclusion bodies can sometimes lead to the solubilisation and the recovery of active proteins, the process is still very empirical, uncertain and of low efficiency.