Cytidine deaminase 2 is required for VLRB antibody gene assembly in lampreys
Résumé
The antibodies of jawless vertebrates consist of leucine-rich repeat arrays encoded by somatically assembled VLRB genes. It is unknown how the incomplete germline VLRB loci are converted into functional antibody genes during B lymphocyte development in lampreys. In Lampetra planeri larvae lacking the cytidine deaminase CDA2 gene, VLRB assembly fails, whereas the T lineage-associated VLRA and VLRC antigen receptor gene assemblies occur normally. Thus, CDA2 acts in a B cell lineage-specific fashion to support the somatic diversification of VLRB antibody genes. CDA2 is closely related to activation-induced cytidine deaminase (AID), which is essential for the elaboration of immunoglobulin gene repertoires in jawed vertebrates. Our results thus identify a convergent mechanism of antigen receptor gene assembly and diversification that independently evolved in the two sister branches of vertebrates.
Auteurs, date et publication :
Auteurs Ryo Morimoto , Connor O’meara , Stephen Holland , Inês Trancoso , Ahmed Souissi , Michael Schorpp , Danièle Vassaux , Norimasa Iwanami , Orlando Giorgetti , Guillaume Evanno , Thomas Boehm
Publication : Science Immunology
Date : 2020
Volume : 5
Issue : 45
Pages : eaba0925