Somatic hypermutation (SHM) and gene conversion (GCV) are closely related processes that increase the diversity the primary immunoglobulin repertoire. In both processes the activation-induced cytidine deaminase (AID) converts cytosine residues to uracils within the DNA of the immunoglobulin (Ig) genes in a transcription-dependent manner, and subsequent error-prone repair processes lead to changes in the antigen recognition site of the encoded receptors. This activity is specifically recruited to the Ig loci by unknown mechanisms.
View Article and Find Full Text PDFThe Fragile X mental retardation syndrome is the largest source of inherited mental retardation. The syndrome usually results from the transcriptional silencing of the fragile X mental retardation gene (FMR1). To date the most prominent reported neuronal abnormalities for the fragile X mental retardation syndrome include a higher density of long thin spines similar to those found in sensory deprived and developing tissue, suggesting a possible deficit in pruning of immature spines.
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