Transcription of mouse kappa chain genes: implications for allelic exclusion.
The nuclear RNA from a large variety of kappa-producing plasmacytomas was size fractionated and analyzed with a series of cloned probes representing sequences encoding variable (V), joining (J), and constant (C) regions and selected intervening sequences. All of the plasmacytomas produce a nuclear RNA component that contains V kappa and C kappa sequences as well as the intervening sequence between J kappa and C kappa, and that has a distinctive size depending on which of the four J kappa segments is expressed (i.e., is present in the secreted kappa chain). These RNAs are the precursors of kappa mRNAs, which are transcribed from productively rearranged C kappa genes. Half of the plasmacytomas examined produce, in addition to a kappa mRNA precursor, a discrete component of about 8.4 kilobases that contains C kappa and upstream flanking sequences but lacks the expressed V region sequence. The ability to produce this component is always associated with the persistence in the tumor genome of an unrearranged (germline) J kappa-C kappa region. In tumors rearranged at both kappa loci the nonproductive allele is either transcriptionally silent or, in a minority of cases, transcribed and processed into a "fragment" mRNA lacking V region sequences. These results reveal that allelic exclusion can be effected at several levels of gene expression. They also provide some insight into the relative contributions of the V and C gene elements to this expression.
D000483:Alleles; D002467:Cell Nucleus; D004274:DNA, Recombinant; D005796:Genes; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D009194:Myeloma Proteins / Q000235:genetics; D009374:Neoplasms, Experimental / Q000276:immunology; D009694:Nucleic Acid Precursors / Q000235:genetics; D010954:Plasmacytoma / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D014158:Transcription, Genetic
D004274:DNA, Recombinant; D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains; D009194:Myeloma Proteins; D009694:Nucleic Acid Precursors; D012333:RNA, Messenger; D012334:RNA, Neoplasm