Identification of enhancer sequences 3' of the rabbit Ig kappa L chain loci.
The rabbit is useful for studies of Ig L chain gene expression because of a great disparity in expression of two isotypic forms of the kappa L chain. Normally, K1 is expressed at high levels and K2 is almost silent; expression of K2 increases in mutant or experimentally allotype-suppressed animals. The reasons for the preferential utilization of the K1 isotype have not been fully elucidated. We were interested in looking for second enhancers 3' of the C kappa genes because the absence of a 3' enhancer in the K2 locus could explain the preferential utilization of the K1 isotype. However, we found a strong region of enhancer activity about 7 kb downstream of the C kappa 2 gene. Sequences in this region are highly conserved between rabbit, man, and mouse. There also appears to be a homologous 3' enhancer region in the rabbit K1 locus. We also confirmed earlier reports that the rabbit K1 intron enhancer is inactive in transient transfections into mouse B cells but find that the same construct has low but significant activity in a human B cell line. In a comparable construct the K2 intron enhancer is without activity suggesting possible differential activity of the intronic enhancers.
Hole
N J
NJ
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
Harindranath
N
N
Young-Cooper
G O
GO
Garcia
R
R
Mage
R G
RG
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004742:Enhancer Elements, Genetic; D005803:Genes, Immunoglobulin; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D011817:Rabbits; D012689:Sequence Homology, Nucleic Acid
D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains