1512-Co-option Promotes Antibody Diversification

The research identifies a fundamental mechanism for antibody diversity, explaining how the enzyme AID specifically targets immunoglobulin genes for somatic hypermutation. Scientists discovered that ancient, non-functional LINE-1 retrotransposons located upstream of variable genes serve as a recruitment platform for the HUSH complex. During B cell activation, bidirectional transcription from the variable gene promoter creates antisense RNA that includes these retrotransposons, triggering a silencing response that inadvertently draws AID to the locus. Experimental evidence from knockout mice and engineered cell lines confirms that removing these genomic fossils significantly reduces the frequency of antibody mutations. Conversely, inserting these elements at other locations can induce mutation in off-target genes. This study reveals that the immune system has repurposed an ancient innate defense mechanism against mobile genetic elements to drive the adaptive evolution of high-affinity antibodies.References:Lauring M C, Yang M, Sarode A, et al. Co-option of retrotransposons promotes antibody diversification[J]. Cell, 2026.前往小宇宙评论区与主播互动