Interleukin 7 regulates switch transcription in developing B cells
Résumé
Class switch recombination (CSR) enables activated mature B cells to change immunoglobulin (Ig) isotype expression from IgM to IgG, IgE, or IgA. The process requires activation-induced cytidine deaminase (AID) expression and transcription of the target sequences at the Ig heavy chain (IgH) constant locus, which is composed of multiple constant (CH) genes, each specifying an Ig isotype.1 The CH genes are organized in transcription units made up of I promoters/exons upstream of highly repetitive sequences called switch (S) sequences and the CH exons. Signal-dependent induction of switch transcription at downstream S sequences is required for recombination with the constitutively transcribed Sµ sequence, the universal switch donor site. CSR can also occur in developing B cells, albeit at a lower frequency than in mature cells. The signaling pathways and transcriptional regulatory elements that control CSR in developing B cells are still ill-known. There is evidence that signaling through Toll-like receptors induces AID expression and CSR at early developmental stages and some cis-acting elements are involved in preventing switch transcription in developing cells.
Fichier principal
Interleukin 7 regulates switch transcription in developing B cells.pdf (455.47 Ko)
Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)