Specific transcription of the unrearranged TCR V beta 8.2 gene in lymphoid tissues occurs independently of V(D)J rearrangement.
A truncated T cell receptor (TCR) V beta 8.2 polypeptide expressed on the surface of a precursor lymphoid cell line and on a subset of mesenteric lymph node cells has previously been shown to be encoded by transcripts from unrearranged V beta 8 genes. Germline V beta 8 transcription has now been demonstrated in multiple lymphoid and non-lymphoid tissues in mice of varying ages and in cultured cell lines by reverse transcription-polymerase chain reaction (RT-PCR). Significant levels of V beta 8 germline transcription were found in thymus, spleen, liver and bone marrow and in all lymphoid cell lines studied. Germline V beta 8 transcription in the liver dropped as mice aged, and increased in the bone marrow. Germline V beta 8 transcription was also detectable in thymus, spleen, liver and bone marrow of RAG-1-/- mice. This indicated that it is not dependent upon the presence of mature lymphoid cells, nor necessarily related to V(D)J rearrangement events. Semi-quantitative polymerase chain reaction (PCR) and hybridization with oligonucleotides specific for V beta 8.1, 8.2 and 8.3 showed that the V beta 8.2 gene produced at least 90% of all the germline V beta 8 transcripts in all of the tissues examined. The significance of these results in lymphoid cell development and for models of the regulation of V(D)J rearrangement are discussed.
Jolly
C J
CJ
Division of Biochemistry and Molecular Biology, School of Life Sciences, Australian National University, Canberra, Australia.
O'Neill
H C
HC
D017398:Alternative Splicing / Q000235:genetics / Q000502:physiology; D000818:Animals; D000916:Antibody Diversity / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D003001:Cloning, Molecular; D005091:Exons / Q000235:genetics; D015870:Gene Expression; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor / Q000235:genetics*; D005803:Genes, Immunoglobulin / Q000235:genetics* / Q000502:physiology; D005854:Germ Cells / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008221:Lymphoid Tissue / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D016133:Polymerase Chain Reaction; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D014158:Transcription, Genetic
D016693:Receptors, Antigen, T-Cell, alpha-beta