Germline transcription of multiple TCR-Vβ genes in cloned T-cell lines

Abstract

The functional significance of germline transcription of T cell receptor (TCR) beta chain variable (V) region genes is under investigation. The accepted model is that transcriptional activation of germline TCR genes is associated with the rearrangement process during T-cell development. By this model, germline expression of a subset of TCR- Vβ genes might be expected in early T cells which have not yet undergone rearrangement. Germline transcription of TCR- Vβ genes was analysed using the reverse transcriptase (RT)-PCR in a clonal T-cell precursor line C1-V13D, a clonal pre-B cell line RAW112 and a mature T helper cell line D10.G4.1. Evidence is presented for germline transcription of TCR-Vβ8.2 and TCR-Vβ2.1 genes in all three cell lines, although expression in RAW112 was very weak. C1-V13D cells expressed very high levels of the whole range of transcripts including Vβ2.1, Vβ5.1, Vβ5.2, Vβ6.1, Vβ7.1, Vβ8.1, Vβ8.2, Vβ8.3 and Vβ13.1. However, D10.G4.1 cells expressed a subset of transcripts with apparently lower levels of expression, including Vβ2.1, Vβ5.1, Vβ5.2, Vβ6.1, Vβ8.2 and Vβ8.3. These results raise questions about the significance and possible function of germline transcripts and/or their encoded products in early lymphoid cells and in T cells at different stages of development. Show more