Assembly of the kappa preB receptor requires a V kappa-like protein encoded by a germline transcript.
By confining germline transcription as a byproduct of the mechanisms inherent to genetic rearrangements, the translation of respective mRNAs and their biological relevance might have been overlooked. Here we report the identification, cloning, and biochemical characterization of a human Vkappa-like protein that is encoded by a germline transcript. This surrogate protein assembles with the immunoglobulin mu heavy chain at the surface of B cell progenitors and precursors to form a kappa-like antigen receptor. These findings support the notion that germline transcription is not futile and stress the flexibility in eukaryotic gene usage and expression. In addition, the present study confirms the co-existence of surrogate lambda and kappa receptors that are proposed to work in concert to promote B lymphocyte maturation.
Rangel
Roberto
R
Department of Immunology, M. D. Anderson Cancer Center, The University of Texas, Houston, Texas 77054, USA.
McKeller
Morgan R
MR
Sims-Mourtada
Jennifer C
JC
Kashi
Cristina
C
Cain
Kelly
K
Wieder
Eric D
ED
Molldrem
Jeffrey J
JJ
Pham
Lan V
LV
Ford
Richard J
RJ
Yotnda
Patricia
P
Guret
Christiane
C
Francés
Véronique
V
Martinez-Valdez
Hector
H
D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D002460:Cell Line; D018095:Germ-Line Mutation / Q000235:genetics*; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D019169:Jurkat Cells; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D054420:Pre-B Cell Receptors; D011947:Receptors, Antigen, B-Cell; D014158:Transcription, Genetic / Q000235:genetics*
D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D008562:Membrane Glycoproteins; D054420:Pre-B Cell Receptors; D011947:Receptors, Antigen, B-Cell