Immunoglobulins and their Genes

Antibody genes are rearranged in antibody-producing cells.

Immunoglobulins consist of heavy and light chains and are synthesized by plasma cells and some lymphocytes.
Each the heavy and the light chains contain domains variable in amino acid sequence at the N-terminus and domain(s) of the same sequence in each immunoglobulin of that subclass at the C-terminus.
cDNA probes specific for each the variable and the constant region parts of murine light chains were hybridized to Southern blots of restriction digests of DNA from mouse embryos, mouse liver and cultured plasmocytoma cells from which the cDNA probes had been made.

A rearrangement of the V region DNA occurred during differentiation, such that the V-region sequence is on a different sized restriction fragment in immunoglobulin producing cells.
A rearrangement of C-region DNA also occurred in this differentiation.
Rearranged V and C DNA sequences are on the same restriction fragment, implying that rearrangement brings previously distant sequences together.
The DNA of immunoglobulin producing cells is not identical to that of germ line cells.

Information provided by: http://opbs.okstate.edu