Characterization and genetic diversity of the sturgeon Acipenser schrenskii Ig heavy chain.

It is still unknown about the VH gene organization and diversity of the immunoglobulin (Ig) heavy chain locus in Amur sturgeon. In this study, Ig heavy chain alleles were cloned by RT-PCR using the specific primers. Sequence analysis showed that Amur sturgeon's VH regions belonged to the same family with higher than 90% identities of their leader peptide (LP). Moreover, a number of conserved motifs in the D segment were identified, and the variability of the CDR3 region was substantial. Further, we speculated that there were at least 12 different JH segments in the locus, contributing to the antibody repertoire of the sturgeon. The genetic diversity of the sturgeon Ig should be associated with the random rearrangement of VH, D and JH segments, action of exonuclease and insertion of N and/or probably P nucleotides at the site of rearrangement.