Abstract
We have isolated cDNA clones complementary to a truncated immunoglobulin heavy-chain Cε RNA transcript previously found to be induced in B lymphoid cells by treatment with lipopolysaccharide (LPS) combined with interleukin-4 (IL-4). We demonstrate that this transcript initiates from a promoter upstream of the germ line ε class-switch recombination region (Sε region). The major germ line Cε transcript contains a small 5′ exon contributed by sequences upstream of the Sε region spliced to the normal Cε exons. Treatment of splenic B lymphoid cells with LPS plus IL-4 induces the expression of transcripts from the germ line ε transcription unit followed by expression of normal immunoglobulin ε heavy-chain mRNA. Furthermore, we demonstrate that similar treatment of transformed precursor B cell lines induces the expression of germ line ε transcripts followed by class switching to ε expression in these lines. This is the first demonstration of switching to ε in cells of the pre-B stage. The general structure of the germ line ε transcript and transcription unit is similar to that previously characterized for germ line γ2b transcripts. However, expression of these two germ line transcription units in B-lineage cells is inversely regulated by IL-4 (plus LPS) treatment, correlating with the effects of these treatments on switching to these loci.
Original language | English (US) |
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Pages (from-to) | 1672-1679 |
Number of pages | 8 |
Journal | Molecular and cellular biology |
Volume | 10 |
Issue number | 4 |
State | Published - 1990 |
Externally published | Yes |
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology