Question

Kappa is one of the subgroups of light chains. If you were to make a Kappa light chain, you choose from how many different Vkappa genes (as the V portion of the final gene)?

Answer 1

When making a kappa light chain, there are 40 different Vkappa genes to choose from. DNA recombinase facilitates a random selection and splicing process that generates a diverse repertoire of B cell receptors, with each B cell typically having a unique variable chain.

Step-by-step explanation:

When creating a kappa light chain, the V portion of the final gene is chosen from 40 different Vkappa genes. These genes are part of the variable (V) region of the light chain gene in germ-line B cells. Due to the process involving DNA recombinase, which randomly excises most of these segments and splices one V segment to one J segment, recombination and splicing result in a high number of possible VJ combinations.

As the RNA is processed, all but one V and J segment are spliced out, allowing for each differentiated B cell in the human body to typically have a unique variable chain. This diversity in the V region is crucial for the immune system's ability to recognize a multitude of antigens. The constant domain (CK) remains the same for all antibodies and does not participate in antigen binding.