The Fc epsilon RII/CD23 gene is actively transcribed during all stages of murine B-lymphocyte development.
It is generally accepted that the expression of Fc epsilon RII/CD23 on the surface of the B-lineage cells is restricted to the stage of the resting, mature (sIgM+/sIgD+) B-lymphocyte. However, it is unknown whether activation of the Fc epsilon RII/CD23 gene is also restricted to the stage of the mature B-lymphocyte. To address this question we investigated a panel of B-lineage cell lines for the presence of transcripts encoding Fc epsilon RII/CD23. We detected transcripts in 16 of 26 B-lineage cell lines representing the entire spectrum of B-cell development. In most cases (13 of 16) active transcription of the murine Fc epsilon RII/CD23 gene was not coupled with the expression of cell surface Fc epsilon RII/CD23 expression did not hold for all murine B-cell lines. One post-switch B-cell line (sIgM-/sIgG+) expressed Fc epsilon RII/CD23 on the cell surface and another could be induced with IL-4 and LPS to express surface Fc epsilon RII/CD23. Transcription of the murine CD23 gene in the absence of cell surface expression of Fc epsilon RII/CD23 does not appear to simply be an aberrant feature of transformed B-cells since we found transcripts, but not surface expression, in some normal splenic and peritoneal B-lymphocytes. Our findings suggest that the potential for expression of Fc epsilon RII/CD23 may occur over a much broader development window of the B-lineage than previously suspected. Transcription of the Fc epsilon RII/CD23 gene, in the absence of detectable cell surface protein expression in B-lineage cell lines, and in sort-purified B-lymphocyte subpopulations, implies that in addition to regulatory mechanisms already known, murine CD23 is also regulated through post-transcriptional mechanisms that have not yet been characterized.
Hagen
M
M
Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA.
Sacco
R E
RE
Sandor
M
M
Best
C
C
Nambu
M
M
Lynch
R G
RG
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D001483:Base Sequence; D002454:Cell Differentiation; D002460:Cell Line; D005434:Flow Cytometry; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017455:Receptors, IgE / Q000096:biosynthesis* / Q000235:genetics; D014158:Transcription, Genetic
D017455:Receptors, IgE