COMPARISON OF THE IMMUNOGLOBULIN HEAVY-CHAIN COMPLEMENTARITY-DETERMINING REGION-3 STRUCTURE AMONG THE DNA-SEQUENCES AND THE MU-TRANSCRIPT AND GAMMA-TRANSCRIPT IN HUMAN B-LINEAGE CELLS
H. Kiyoi et al., COMPARISON OF THE IMMUNOGLOBULIN HEAVY-CHAIN COMPLEMENTARITY-DETERMINING REGION-3 STRUCTURE AMONG THE DNA-SEQUENCES AND THE MU-TRANSCRIPT AND GAMMA-TRANSCRIPT IN HUMAN B-LINEAGE CELLS, Immunology, 89(3), 1996, pp. 324-330
To study the recombinational significance of the (immunoglobulin heavy
) IgH chain gene in human B-cell development, we compared the compleme
ntarity determining region (CDR)-3 sequences of the DNA and the mu-tra
nscripts from human normal pre-B cells and mature B cells, and the gam
ma-transcripts from bone marrow cells. The CDR-3 sequences were longer
in the DNA than in the mu- and gamma-transcripts, and this was indepe
ndent of whether or not the rearrangement was productive. The DLR fami
ly genes were less frequently used in the mu- and gamma-transcripts. W
hen translated into amino acids, all CDR-3 sequences from the mu- and
gamma-transcripts were productive, although 26.2% of the DNA sequences
had stop codons in the D element and/or frameshifts of the ts. The CD
R-3 of the productive DNA sequences in pre-B cells frequently (26.6%)
contained at least three continuous hydrophobic amino acids, which wer
e mainly coded by the DLR and DXP family genes at the third reading fr
ame. However, such motifs were rare in the mu-transcripts of pre-B (7.
7%) and mature B cells (3.9%), and in the gamma-transcripts of bone ma
rrow cells (1.1%) as well as in the DNA of mature B cells (10.4%). The
se findings suggested that the length and/or hydrophobicity of the IgH
CDR-3 might play a role in the selection mechanisms of B-cell develop
ment.