The human pre-B cell receptor: structural constraints for a tentative model of the pseudo-light (psi L) chain.
In human pre-B cells, the mu chain is associated with a surrogate light chain composed of the lambda-like and Vpre-B gene products. This pre-B cell receptor presumably triggers early steps of B cell differentiation, We have determined the NH2-terminal amino acid sequence of the lambda-like chain, showing that the mature chain results from the cleavage of a leader segment of 44 residues, leaving a polypeptide of 169 amino acids having partial features of the Ig light chain domains, with the exception of the first 50 amino acid NH2-terminal region. We have completed the nucleotide sequence of the Vpre-B gene, which appears to contain 126 residues in its mature form of which the 24 COOH-terminal portion was not Ig-related. Analysis of transfectants has provided direct evidence that lambda-like and Vpre-B chains assemble together even in the absence of heavy chain, prompting the search for a structural basis of this interaction. Comparison with the domain organization of the regular Ig lambda chain suggests that most of the psi L chain can be accommodated within a CL-VL-like structure, with an extra "subdomain" contributed by the non-Ig-like portions of both the lambda-like and Vpre-B polypeptides.
Guelpa-Fonlupt
V
V
Centre d'Immunologie de Marsielle-Luminy (CIML), France.
Bossy
D
D
Alzari
P
P
Fumoux
F
F
Fougereau
M
M
Schiff
C
C
D000595:Amino Acid Sequence; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D001483:Base Sequence; D015153:Blotting, Western; D002454:Cell Differentiation / Q000276:immunology; D002460:Cell Line; D003001:Cloning, Molecular; D003198:Computer Simulation; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000276:immunology*; D007146:Immunoglobulin lambda-Chains / Q000276:immunology; D018448:Models, Immunological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011971:Receptors, Immunologic / Q000737:chemistry*; D014162:Transfection
D007147:Immunoglobulin Light Chains; D007146:Immunoglobulin lambda-Chains; D011971:Receptors, Immunologic