Inclusion bodies

Source: Wikipedia, the free encyclopedia.

Inclusion bodies are aggregates of specific types of

muscle cells affected by inclusion body myositis and hereditary inclusion body myopathy.[1]

Inclusion bodies in neurons may be accumulated in the cytoplasm or nucleus, and are associated with many neurodegenerative diseases.[2] Inclusion bodies in neurodegenerative diseases are

amyotrophic lateral sclerosis.[5]

Other usual cell inclusions are often temporary inclusions of accumulated proteins, fats, secretory granules or other insoluble components.[6]

Inclusion bodies are found in bacteria as particles of aggregated protein. They have a higher density than many other cell components but are porous.

capsid proteins
. Inclusion bodies contain very little host protein, ribosomal components or DNA/RNA fragments. They often almost exclusively contain the over-expressed protein and aggregation and has been reported to be reversible. It has been suggested that inclusion bodies are dynamic structures formed by an unbalanced equilibrium between aggregated and soluble proteins of
non-covalent hydrophobic or ionic interactions or a combination of both.[citation needed
]

Composition

Inclusion bodies have a non-unit (single) lipid membrane[

misfolded protein. However, this has been contested, as green fluorescent protein will sometimes fluoresce in inclusion bodies, which indicates some resemblance of the native structure and researchers have recovered folded protein from inclusion bodies.[8][9][10]

Mechanism of formation

When

precipitate by saturating its environment.[citation needed
]

In neurons

Inclusion bodies are aggregates of protein associated with many

muscle cells affected by inclusion body myositis and hereditary inclusion body myopathy.[1]

Inclusion bodies in neurodegenerative diseases are aggregates of

amyotrophic lateral sclerosis.[5]

In red blood cells

Normally a red blood cell does not contain inclusions in the cytoplasm. However, it may be seen because of certain hematologic disorders.

There are three kinds of red blood cell inclusions:

  1. Developmental organelles
    1. Howell-Jolly bodies: small, round fragments of the nucleus resulting from karyorrhexis or nuclear disintegration of the late reticulocyte and stain reddish-blue with Wright's stain
      .
    2. erythrocytes
      on a dried Wright's stain.
    3. erythrocyte
      in a Wright stain.
    4. Polychromatophilic red cells – young red cells that no longer have nucleus but still contain some RNA.
    5. erythrocytes are destroyed before being released from the bone marrow
      .
  2. Abnormal hemoglobin precipitation
    1. Heinz bodies[11]
      – round bodies, refractile inclusions not visible on a Wright's stain film. They are best identified by supravital staining with basic dyes.
    2. erythrocytes after four drops of blood is incubated with 0.5mL of Brilliant cresyl blue
      for 20 minutes at 37 °C.
  3. Protozoan inclusion
    1. Malaria
    2. Babesia

In white blood cells

In viruses

See also: Viroplasm
Canine distemper virus with cytoplasmic inclusion body (Blood smear, Wright's stain)

Examples of viral inclusion bodies in animals are

Cytoplasmic eosinophilic (acidophilic)-

Nuclear eosinophilic (acidophilic)-

Nuclear basophilic-

Both nuclear and cytoplasmic-

Examples of viral inclusion bodies in plants[13] include aggregations of virus particles (like those for Cucumber mosaic virus[14]) and aggregations of viral proteins (like the cylindrical inclusions of potyviruses[15]). Depending on the plant and the plant virus family these inclusions can be found in epidermal cells, mesophyll cells, and stomatal cells when plant tissue is properly stained.[16]

In bacteria

Polyhydroxyalkanoates (PHA) are produced by bacteria as inclusion bodies. The size of PHA granules are limited in E. coli, due to its small size.[17] Bacterial cell's inclusion bodies are not as abundant intracellularly, in comparison to eukaryotic cells.

Polymeric R bodies are found in the bacterial cytoplasm of some taxa, and thought to be involved in toxin delivery.[18]

Isolation of proteins

Between 70% and 80% of recombinant proteins expressed E. coli are contained in inclusion bodies (i.e., protein aggregates).[19] The purification of the expressed proteins from inclusion bodies usually require two main steps: extraction of inclusion bodies from the bacteria followed by the solubilisation of the purified inclusion bodies. 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. Renaturation follows the treatment with denaturing agents and often consists of dialysis and/or use of molecules that promote the refolding of denatured proteins (including chaotopic agents[7] and chaperones).[20]

Pseudo-inclusions

Pseudo-inclusions are invaginations of the cytoplasm into the

papillary thyroid carcinoma.[21]

Diseases involving inclusion bodies

See also: List of inclusion bodies that aid in diagnosis of cutaneous conditions
Disease Affected cells
Inclusion body myositis muscle cells
Amyotrophic lateral sclerosis
 motor neurons
Dementia with Lewy bodies cerebral neurons

Inclusion body diseases differ from amyloid diseases in that inclusion bodies are necessarily intracellular aggregates of protein, where amyloid can be intracellular or extracellular. Amyloid also necessitates protein polymerization where inclusion bodies do not.[22]

Preventing inclusion bodies in bacteria

Inclusion bodies are often made of denatured aggregates of inactive 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. Several techniques have been developed over the years to prevent the formation of inclusion bodies. These techniques include:

  • The use of weaker promoters to slowdown the rate of protein expression
  • The use of low copy number plasmids[23]
  • The co-expression of chaperone (such as GroES-GroEL and DnaK-DnaJ-GrpE)[24]
  • The use of specific E. coli strains such as (AD494 and Origami)[25]
  • Fusing the target protein to a soluble partner[26]
  • Lowering the expression temperature

See also

References

  1. ^ a b "Sporadic Inclusion Body Myositis". NORD (National Organization for Rare Disorders). Retrieved 12 March 2021.
  2. ^
    PMID 29947927
    .
  3. ^ "Encephalopathy, familial, with neuroserpin inclusion bodies (Concept Id: C1858680) – MedGen – NCBI". www.ncbi.nlm.nih.gov. Retrieved 6 April 2021.
  4. ^
    S2CID 4423699
    .
  5. ^
    S2CID 1002680
    .
  6. ISBN 9781416062578
    .
  7. ^
    S2CID 24807019
    . Inclusion bodies are dense electron-refractile particles of aggregated protein found in both the cytoplasmic and periplasmic spaces of E. coli during high-level expression of heterologous protein. It is generally assumed that high level expression of non-native protein (higher than 2% of cellular protein) and highly hydrophobic protein is more prone to lead to accumulation as inclusion bodies in E. coli. In the case of proteins having disulfide bonds, formation of protein aggregates as inclusion bodies is anticipated since the reducing environment of bacterial cytosol inhibits the formation of disulfide bonds. The diameter of spherical bacterial inclusion bodies varies from 0.5–1.3 μm and the protein aggregates have either an amorphous or paracrystalline nature depending on the localization. Inclusion bodies have higher density (~1.3 mg ml−1) than many of the cellular components, and thus can be easily separated by high-speed centrifugation after cell disruption. Inclusion bodies despite being dense particles are highly hydrated and have a porous architecture.
  8. PMID 15670769
    .
  9. PMID 8140090
    .
  10. PMID 14652027
    .
  11. ^ Heinz+Bodies at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
  12. PMID 2379881
    .
  13. ^ "Plant Viruses Found in Florida and Their Inclusions". University of Florida. Archived from the original on 24 March 2012.{{cite web}}: CS1 maint: unfit URL (link)
  14. ^ "Inclusions of Cucumber Mosaic Cucumovirus (CMV)". University of Florida. Archived from the original on 19 February 2012.{{cite web}}: CS1 maint: unfit URL (link)
  15. ^ "Inclusions of Potyviridae Found In Florida". University of Florida. Archived from the original on 19 February 2012.{{cite web}}: CS1 maint: unfit URL (link)
  16. ^ "Materials and Methods for the Detection of Viral Inclusions". University of Florida. Archived from the original on 19 February 2012.{{cite web}}: CS1 maint: unfit URL (link)
  17. PMID 25868707
    .
  18. PMID 23450193
    .
  19. ^ Yang, Zhong, et al. "Highly efficient production of soluble proteins from insoluble inclusion bodies by a two-step-denaturing and refolding method." PloS one 6.7 (2011): e22981.
  20. S2CID 195739183
    .
  21. ISBN 978-1-4160-2973-1
    . 8th edition.
  22. S2CID 205383483
    .
  23. PMID 23829073
    .
  24. PMID 7669342
    .
  25. PMID 12059151
    .
  26. S2CID 23539643
    .
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