Immunoglobulin lambda light-chain-related genes 14.1 and 16.1 are expressed in pre-B cells and may encode the human immunoglobulin omega light-chain protein.
Human pre-B cells, which produce immunoglobulin heavy chain but do not produce immunoglobulin light chain, are shown to contain a 1-kilobase transcript homologous to immunoglobulin lambda light-chain genes. Detailed analysis of RNA and cDNA clones derived from these transcripts reveals that they originate from the distinct immunoglobulin lambda-like genes 14.1/16.1. Sequence analysis of these clones reveals a long open reading frame, beginning with an ATG, capable of encoding a protein of 214 amino acids with an unprocessed molecular weight of 22,944. The C-terminal half of this predicted protein is highly homologous to immunoglobulin lambda light-chain joining and constant region protein sequence, while the amino-terminal end does not share homology with variable regions. Unlike immunoglobulin genes, these genes do not undergo rearrangement prior to expression. Analysis of a panel of 26 hematopoietic cell lines reveals that expression of 14.1/16.1 is limited to pre-B cells and one B-cell line, which, like the pre-B cells, is surface immunoglobulin negative. Antisera raised against a peptide whose sequence was predicted from the 14.1 cDNA sequence identifies a 22-kDa protein in human pre-B cells. Immunoprecipitation of immunoglobulin mu-chain from these pre-B cells with anti-immunoglobulin mu antibody coprecipitates a 22-kDa protein, which is a candidate for the human immunoglobulin omega light-chain protein and may be the protein product of the 14.1/16.1 genes.
Hollis
G F
GF
Department of Biological Sciences, Monsanto Co., Saint Louis, MO 63198.
Evans
R J
RJ
Stafford-Hollis
J M
JM
Korsmeyer
S J
SJ
McKearn
J P
JP
D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D015139:Blotting, Southern; D002460:Cell Line; D003001:Cloning, Molecular; D015322:Gene Rearrangement, B-Lymphocyte; D005803:Genes, Immunoglobulin; D006801:Humans; D015151:Immunoblotting; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007146:Immunoglobulin lambda-Chains / Q000235:genetics*; D007148:Immunoglobulin mu-Chains / Q000235:genetics; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D014407:Tumor Cells, Cultured / Q000276:immunology
D007147:Immunoglobulin Light Chains; D007146:Immunoglobulin lambda-Chains; D007148:Immunoglobulin mu-Chains