Genetics Question: Plasma Isotype Reversion?

[aftp2020]

It's my understanding that through the process of class switch recombination, loci fragments are lost in the plasma cell's genome. Does this mean that reversion to a prior isotype cannot be achieved and that isotype switching is always a linear progression within the differentiated cell?

 

"While class switch recombination is mostly a deletional process, rearranging a chromosome in "cis", it can also occur (in 10 to 20% of cases, depending upon the Ig class) as an inter-chromosomal translocation mixing immunoglobulin heavy chain genes from both alleles." (https://www.wikiwand.com/en/Immunoglobulin_class_switching)

 

I further understand that the deletional process utilizes NHEJ. Could this trans acting translocation accomplish restorative function of a prior isotype?

 

Thanks

Edited January 5, 2020 by aftp2020

[Vmedvil2]

Hello,

 

I'm preparing for graduate studies and often have questions I cannot seem to clarify with preliminary research. I thought this may be a great avenue by which to accomplish that among the scientific community.

 

Forgive me if this is not the correct sub-forum for this type of posting; I've just created an account and am receptive to instruction otherwise.

 

It's my understanding that through the process of class switch recombination, loci fragments are lost in the plasma cell's genome. Does this mean that reversion to a prior isotype cannot be achieved and that isotype switching is always a linear progression within the differentiated cell?

 

"While class switch recombination is mostly a deletional process, rearranging a chromosome in "cis", it can also occur (in 10 to 20% of cases, depending upon the Ig class) as an inter-chromosomal translocation mixing immunoglobulin heavy chain genes from both alleles." (https://www.wikiwand.com/en/Immunoglobulin_class_switching)

 

I further understand that the deletional process utilizes NHEJ. Could this trans acting translocation accomplish restorative function of a prior isotype?

 

Thanks!

 

If the DNA for said Antigen is lost then there is no hope of recovery of the original antigen though the cell could just do the switch recombination again if the need arises for the antigen to be present. From my understanding there is a very small deletion of the DNA the overall structure of the antigen is kept via the Heavy Chains DNA being kept, the structure of the overall antigen is being kept it is just the end of the antigen that has a different head thus it can be generated as the cell requires again via the same process. It is not a linear progression as only certain DNA fragments can take the place of those parts meaning only a certain number of combinations before it will use the same combination again being generated by that process. Basically, only the a, γ, α or ε segments are changed thus if new ones of the same type are joined there you would receive the exact same antigen, so as long as the information for the creation of the antigen segments are not lost there is still the chance upon need by the cell of the same antigens being created. If you wanted to receive a certain antigen that has been created you could just sequence that section of DNA and synthesize that antigen from that template that was sequenced to always receive the same antigen if it is of interest, then insert that section of DNA into the cell and it would always display that antigen.

Edited January 4, 2020 by VictorMedvil