Structure and expression of germline epsilon transcripts in human B cells induced by interleukin 4 to switch to IgE production.
Interleukin 4 (IL-4)-induced IgE production coincides with the appearance of the 2.2-kb productive epsilon-mRNA, but is preceded by synthesis of a 1.7-kb epsilon-RNA. Analysis of cDNA copies of the 5' end of this RNA indicated that the 1.7-kb epsilon-RNA is a germline epsilon immunoglobulin heavy chain transcript with an exon mapping 5' to the switch region. Transcription through switch regions has been implicated in the control of class switching. However, IL-4 or cloned CD4+ T cells were able to induce germline epsilon transcripts without inducing IgE synthesis, for which both signals were required. These results indicate that induction of human germline epsilon-RNA does not necessarily result in IgE synthesis, and that additional regulatory mechanisms are involved in class switching.
DNAX Research Institute, Palo Alto, California 94304.
J F
JF
Gauchat
D A
DA
Lebman
R L
RL
Coffman
H
H
Gascan
J E
JE
de Vries
D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D005803:Genes, Immunoglobulin; D005809:Genes, Regulator; D005812:Genes, Switch; D006801:Humans; D007073:Immunoglobulin E / Q000096:biosynthesis / Q000235:genetics*; D007372:Interferons / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology*; D007700:Kinetics; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D014158:Transcription, Genetic
D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D015847:Interleukin-4; D007073:Immunoglobulin E; D007372:Interferons