Evolution of immunoglobulin genes: VH families in the amphibian Xenopus.
AUTOR(ES)
Hsu, E
RESUMO
We have isolated multiple independent cDNA clones that represent mRNA sequences of immunoglobulin heavy chains from the spleen of adult Xenopus laevis. These cDNA clones contained constant (C) region sequences that were either Cmu or a separate C region sequence believed to be Cnu. In individual cDNA clones the C region sequences were associated with independent heavy-chain variable region (VH) sequences that were classifiable into five distinct families. Genomic Southern blotting analyses with family-specific probes indicated that the haploid genome contains a minimum of 80 VH gene segments, a number similar to that found in various mammalian species. Multiple JH and putative DH segments were also identified (J, joining; D, diversity). Analyses of 13 independent VHDJH junctions suggest that combinatorial and junctional diversification mechanisms probably arose early in vertebrate evolution. Finally, comparison of Xenopus VH sequences to those from other vertebrates indicated conservation of V region framework residues that are responsible for the tertiary structure of the Fv throughout evolution.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=298203Documentos Relacionados
- Organization and rearrangement of immunoglobulin M genes in the amphibian Xenopus.
- The genomic organization of immunoglobulin VH genes in Xenopus laevis shows evidence for interspersion of families.
- Evolution of the major histocompatibility complex: molecular cloning of major histocompatibility complex class I from the amphibian Xenopus.
- Evolution of immunoglobulin light chain genes: analysis of Xenopus IgL isotypes and their contribution to antibody diversity.
- The ontogeny of diversification at the immunoglobulin heavy chain locus in Xenopus.