IGH

Role in the organism:

Immunoglobulins are complex proteins that recognize foreign antigens in the body. They bind to these antigens, neutralize them and participate in their destruction. Some immunoglobulins are integrated into the membrane of cells in which antibody secretion is performed. The antibodies consist of two heavy chains (encoded by the IGH locus) and two light chains, encoded by either the IGK locus on chromosome 2 or the IGL locus on chromosome 22. All three loci share unusual properties of the region in which the genes whose products correspond to the antigen-binding region The antibody is divided into a number of alternative segments. These segments were combined at random, at the DNA level during B-lymphocyte maturation, so that each B-cell clone represented a different antibody with different antigenic properties. The IGH locus has 86 variable gene (V) segments, 30 different (D) segments, 9 binding (J) segments and 11 alternative constant regions that determine the class of antibodies (IgG, IgM, IgE, IgA, or IgD) and exert complementary functions of the immune system by binding to complementary proteins (see C6 gene on chromosome 5). Further diversity can be achieved by varying the recombination sites, adding or removing nucleotides to the compounds, and introducing random mutations into the entire sequence of the antigen-binding domain.

Role in the disorder (state):

Mutations in constant regions of the IGH locus can interfere with specific antibody functions and cause a general decline in the immune system. The most striking phenomenon related to the IGH locus is the chromosomal translocation that causes leukemia. This reflects the fact that the IGH gene is expressed at a very high level due to its strong promoter function. Translocations that introduce oncogenes into the framework of this regulatory system result in high levels of gene expression and uncontrolled cell proliferation in the blood lineage.