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Complementation between two cell lines lacking kappa enhancer activity: implications for the developmental control of
1Fox Chase Cancer Center, Philadelphia, PA 19111.
The EMBO Journal
|December 20, 1988
Summary
Somatic cell hybrids reveal that S107 cells lack the NF-kappa B factor but possess the activation system. This enables kappa enhancer activity and transcription, independent of NF-kappa B levels after initial activation.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Plasmacytoma S107 and pre-B cells lack immunoglobulin kappa (Ig kappa) enhancer activity due to absent active NF-kappa B.
- Pre-B cells have a masked form of NF-kappa B, activatable by post-translational modification.
Purpose of the Study:
- To determine if S107 cells lack NF-kappa B or its activation system.
- To investigate the role of NF-kappa B in kappa enhancer activity and transcription.
Main Methods:
- Somatic cell hybridization between S107 and pre-B cells.
- Analysis of NF-kappa B production and activity.
- Assessment of kappa enhancer activity and kappa loci transcription.
- Treatment with bacterial lipopolysaccharide (LPS).
Main Results:
- Hybrids produced active NF-kappa B and activated silent kappa loci.
- S107 cells lack NF-kappa B but retain the activation system.
- LPS treatment increased NF-kappa B and kappa enhancer activity 4-5 fold.
- Kappa loci expression remained unchanged post-LPS, indicating enhancer independence.
Conclusions:
- S107 cells possess the NF-kappa B activation machinery but lack the factor itself.
- A two-step transcriptional process governs kappa loci expression: initial NF-kappa B-dependent activation followed by enhancer-independent maintenance.
- Kappa transcription is ultimately regulated independently of enhancer activity levels.