Allelic exclusion model questioned

Genomic imprinting and allelic exclusion.

In diploid cells, allelic exclusion reduces genes to functional haploidy, because only one of two alleles is active. It is best known in cells producing immunoglobulins, but other examples also exist. X-chromosome inactivation in female mammals is related to allelic exclusion, but in this case the dosage compensation mechanism extends to the whole chromosome. Functional hemizygosity in some mam...

Allelic Exclusion of the TCR

Antigenic Variation and Allelic Exclusion

Cells often express only one gene from a set of two or more. African trypanosomes appear to accomplish this monoallelic expression by segregating the selected gene into a specific nuclear body. The possibility that such a structure might explain monoallelic expression in other multigene systems is discussed here.

Jane Skok: Choreography of allelic exclusion

1514 JEM Vol. 205, No. 7, 2008 Antibody diversity is generated during B cell development by the rearrangement of variable (V), diversity (D), and joining (J) segments of immunoglobulin (Ig) genes. Both alleles of each Ig locus can initiate rearrangement, but only one allele successfully rearranges. As soon as this occurs, the other allele is prevented from following suit. This mechanism, known ...

Functional Allelic Exclusion in T Cells

Over the past decade there have been numerous descriptions of suppressor T cells (Ts) and of factors derived from such cells. Several apparently related, but nonidentical, suppressor regulatory pathways consisting of a variety of T-T interactions have been described (1-4). Our laboratory has concentrated on one of these models of antigen-specific suppression involving the hapten 4-hydroxy3-nitr...