Multiple expression of Ig lambda-chain encoding RNA species in murine plasmacytoma cells

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• Murine plasmacytoma MOPC 315 synthesizes IgA with lambda 2 light chains.
• This plasmacytoma also produces an abnormal lambda 1 polypeptide.

Purpose of the Study:

• Investigate the transcription and translation of immunoglobulin light chain genes in plasmacytoma cells.
• Determine the mechanisms controlling immunoglobulin expression.

Main Methods:

• RNA analysis to identify mRNA transcripts.
• In vitro translation assays to detect polypeptide synthesis.
• Antigenic determinant analysis to identify specific light chains.

Main Results:

• MOPC 315 synthesizes a lambda 1-related polypeptide from a shorter mRNA.
• HOPC-1 produces both lambda 1-encoding mRNA and lambda 2 RNA.
• Lambda 2-producing hybridomas do not synthesize lambda 1 RNA.

Conclusions:

• Plasmacytoma cells can transcribe multiple light chain genes.
• Only one light chain gene product is utilized for complete immunoglobulin synthesis.
• Novel regulatory mechanisms control immunoglobulin gene expression.