Dispersed human immunoglobulin κ light-chain genes

Abstract

The gene segments encoding the constant and variable regions of human immunoglobulin light chains of the kappa type (C kappa, V kappa) have been localized to chromosome 2. The distance between the C kappa and V kappa genes and the number of germline V kappa genes are unknown. As part of our work on the human V kappa locus, we have now mapped two solitary V kappa gene and a cluster of three V kappa genes to chromosomes 1, 15 and 22, respectively. The three genes that have been sequenced are nonprocessed pseudogenes, and the same may be true for the other two genes. This is the first time that V-gene segments have been found outside the C-gene-containing chromosomes. Our finding is relevant to current estimates of the size of the V kappa-gene repertoire. Furthermore, the dispersed gene regions have some unusual characteristics which may help to clarify the mechanism of dispersion.

Localization, analysis and evolution of transposed human immunoglobulin Vκ genes

“…1 for the A regions and the 0 and W regions (pohlenz et al, 1987). The assignment of the L regions to chromosome 2 has been described previously (Lötscher et al, 1986). Even if all steps in the preparation of a cosmid library are carefully controlled, a small amount of ligation artifacts is encountered, which we estimate to be about 3 % (pohlenz et al, 1987).…”

“…To continue the structural work on the human K locus successfully, it was necessary to check systematically the chromosomal localization of V K regions. The method for tbe chromosomallocalization experiments was the same as used previously (Lötscher et al, 1986). Brietly, specific subclones prepared from the various regions were hybridized to a panel of digested DNAs from human-rodent cell hybrids containing different sets ofhuman chromosomes.…”

“…2), respectively. The hybrid celliines are the same as those used in Lötscher et al (1986). Filled spaces indicate the presence ofthe chromosome in the respective cellline; half-filled spaces mean that part ofthe chromosome is present, and empty spaces indicate that the chromosome was not detected by biochemical and cytogenetic analyses.…”

“…In addition, some of the hybridization experiments were carried out in phosphate buffer as described by Church and Gilbert (1984). The mouse-human and hamster-human cell hybrids which were used for the chromosomallocation analyses were the same as in Lötscher et al (1986). The cosmid clones cos 206 and 218 are derived from the cosmid library III (Pohlenz et al, 1987).…”

“…Some orphon V K genes have been localized on chromosomes 1 and 22 (Lötscher et al, 1986) and on other chromosomes (Straubinger et al, 1988a). A c1ustering of putative autonomously replicating sequences has been detected in the 5' tlanks of some V K I orphons indicating that they may have been formed in evolution by over-replication and transposition events (Lötscher et aJ., 1988).…”