MIP 342 Lecture Notes - Cytidine Deaminase, Cytidine, Somatic Hypermutation
11 Jul 2014
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Nucleotide additions by tdt must be in-frame or premature termination and death of cell results. Gene conversion - rare, long slow process except in birds, part of psuedogene is spliced in. Somatic hypermutation occurs via activation induced cytidine deaminase (aicd) and friends. Dna in variable region or in switch region transcription produces local single-stranded. Dna in b cells aid attacks cytidine in single-stranded dna to produce uridine uracil-dna-glycosylase (ung) removes uracil to form apyrimidinic residue apurinic/apyrimidinic endonuclease (ape1) excises ribose to form a single-strand nick in. B-cell precursor rearranges its immunoglobulin genes generation of b-cell receptors in the bone marrow. Immature b cell bound to self cell-surface antigen is removed from the repertoire negative selection in the bone marrow. Mature b cell bound to foreign antigen is activated b cell migrate to the peripheral lymphoid organs. Activation induced cytidine deaminase (aicd) begins to mutate activated b cells" antibodies somatic hypermutation. Class switching begins, igd/igm to igg, iga, ige.
