Transcriptional diversity at the duplicated human CD8β loci

James P. Disanto, Deborah Smith, Derik De Bruin, Elizabeth Lacy, Neal Flomenberg

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


In order to understand the structural organization of the human CD8β locus, genomic clones containing CD8β sequences were isolated and analyzed. Physical linkage of these clones with the CD8α locus using pulsed‐field electrophoresis revealed a duplication of the CD8β locus. CD8B‐1 lies 35 kb upstream from the CD8α locus and contains eight exons, including four alternatively spliced cytoplasmic exons. The CD8B‐2 gene contains six exons and is at present unlinked to CD8B‐1. Analysis of sequences upstream to the leader exon of the CD8B‐1 and CD8B‐2 genes revealed a GC‐rich promoter which lacks canonical “CCAAT” and “TATA” motifs, but which has sites for multiple transcriptional activators and three additional elements which are conserved in the murine CD8β promoter. Seven unique CD8β cDNA isoforms were isolated and characterized, which derive from alternative splicing of the transmembrane and/or cytoplasmic exons. Three cDNA are membrane spanning, while the remaining four isoforms lack a transmembrane region and are potentially secreted. These transcripts are differentially expressed in the thymus and in the periphery. Transaction experiments in murine fibroblasts confirmed that the membrane CD8β isoforms could be expressed as heterodimers with the CD8α chain. The regulated expression of multiple CD8β cytoplasmic isoforms and their potential role in T lymphocyte signal transduction is discussed.

Original languageEnglish (US)
Pages (from-to)320-326
Number of pages7
JournalEuropean Journal of Immunology
Issue number2
StatePublished - Feb 1993
Externally publishedYes


  • Alternative splicing
  • CD8 complex
  • Gene duplication
  • Pulsed‐field gel electrophoresis
  • cDNA isoforms

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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