Deduced amino acid sequences of tumor-derived V_H genes from WM cases, indicating extent of somatic mutation and primer design for alternative transcripts.

Comparisons for WM (WM1-7) are made with the closest germline V_H gene: uppercase, replacement (R) mutation (underlined in J_H); lower case, silent (S) mutation (EMBL accession nos.AJ488538-44). Each mutation was defined by nucleotide exchanges in a single codon, with successive mutations leading in some cases to 2 or 3 distinct R or S events. These are shown as vertically aligned amino acid changes at specific sites. Nucleotide mutations in the last codons of tumor V_H genes were assessed only if followed by at least a 2-base pair homology to the germline gene. Tumor V_Hsequence specific 5′ primers to assess switched transcripts are double-underlined in individual sequences.