A surrogate 15 kDa JC kappa protein is expressed in combination with mu heavy chain by human B cell precursors.
A novel kappa protein, encoded by a germline JC kappa transcript, is expressed by normal and leukemic human B cell precursors. The transcript displays an open reading frame initiated by a non-AUG codon, and predicts a 15 kDa molecule which could be readily confirmed by in vitro translation. Cellular expression was demonstrated by immunofluorescence, precipitation and Western blotting. Furthermore, 2-D gel electrophoresis revealed that germline JC kappa can covalently associate with mu heavy chain at the surface of pre-B cells. We therefore propose that during B cell lymphopoiesis, two alternative pathways could be operative in which mu heavy chain can either associate with lambda 5 or germ-line JC kappa.
Francés
V
V
Schering-Plough, Laboratory for Immunology Research, Dardilly, France.
Pandrau-Garcia
D
D
Guret
C
C
Ho
S
S
Wang
Z
Z
Duvert
V
V
Saeland
S
S
Martinez-Valdez
H
H
D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000378:metabolism*; D001483:Base Sequence; D015153:Blotting, Western; D002474:Cell-Free System; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D005333:Fetus / Q000166:cytology; D015322:Gene Rearrangement, B-Lymphocyte / Q000235:genetics*; D005803:Genes, Immunoglobulin / Q000235:genetics*; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000096:biosynthesis*; D007148:Immunoglobulin mu-Chains / Q000096:biosynthesis*; D007938:Leukemia / Q000235:genetics; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics
D007145:Immunoglobulin kappa-Chains; D007148:Immunoglobulin mu-Chains; D012333:RNA, Messenger