Biology Reference
In-Depth Information
were identical among human, mouse and rabbit. For different antibodies
with different CDR's, their FR's can be identical, suggesting that the
variable regions of antibody light and heavy chains can be assembled from
short segments.
In 1978, Bernard
et al
. were analyzing the nucleotide sequences of mouse
lambda light chain genes in adult and fetus. They discovered that the light
chain variable region gene was assembled from the joining of a V-gene and
a J-minigene, which were physically separated by about 100 kb in the fetal
genome. This process is now known as DNA re-arrangement. In fact, the J-
minigenes code for the amino acid sequences of switch peptides. Special
recombination signal sequences (RSS), consisting of a 7-mer and a 9-mer
separated by a spacer of around 12 or 23 base-pairs, are involved in this re-
arrangement (Fig. 1-7). A 23-bp spacer at the 3'-end of the mouse lambda
light chain V-gene can be joined to a 12-bp spacer at the 5'-end of the J-
mingene. Many different enzymes are required (Slackman
et al
., 1996).
Portions of the nucleotide sequences for the V-gene and J-minigenes of the
mouse lambda light chain, and their RSS are shown in Fig. 1-7. For kappa
light chains, the spacers for their RSS are reversed, i.e. a 12-bp spacer at the
3'-end of the V-gene and a 23-bp spacer at the 5'-end of the J-minigene.
Figure 1-7
. Portions of nucleotide sequences of the fetal and adult mouse lambda light chain
variable region V-gene and J-minigene (modified from Bernard
et al
., 1978).
