Combined deletion of CD8 locus cis-regulatory elements affects initiation but not maintenance of CD8 expression

Immunity. 2002 May;16(5):623-34. doi: 10.1016/s1074-7613(02)00309-6.


Developmental stage-, subset-, and lineage-specific CD8 enhancers have been identified recently by transgenic reporter analyses. Enhancer E8(II) (CIV-4,5) is active in both immature double-positive thymocytes (DP) and mature CD8 single-positive (SP) thymocytes and T cells, whereas E8(I) (CIII-1,2) directs expression only in mature cells. In mice lacking either E8(I) (CIII-1,2) or E8(II) (CIV-4,5), there was no effect on CD8 expression in DP thymocytes. However, deletion of both enhancers resulted in variegated expression of CD8, with appearance of CD4(+)CD8(-) SP thymocytes expressing surface markers characteristic of DP thymocytes. Consequently, fewer mature CD8(+) T cells developed from the reduced pool of DP cells. These results suggest that the initiation of CD8 expression is mediated by cis-regulatory elements that are distinct from any that may be involved in maintenance of expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes / immunology
  • CD8 Antigens / biosynthesis
  • CD8 Antigens / genetics*
  • CD8 Antigens / metabolism*
  • CD8-Positive T-Lymphocytes / immunology*
  • Cell Differentiation
  • Enhancer Elements, Genetic*
  • Epithelium / immunology
  • Flow Cytometry
  • Gene Expression Regulation
  • Mice
  • Organ Culture Techniques
  • Regulatory Sequences, Nucleic Acid
  • Sequence Deletion
  • T-Lymphocyte Subsets / immunology
  • Thymus Gland / immunology*
  • Transcriptional Activation


  • CD8 Antigens
  • CD8 antigen, alpha chain