E. Rouvier et al., CTLA-8, CLONED FROM AN ACTIVATED T-CELL, BEARING AU-RICH MESSENGER-RNA INSTABILITY SEQUENCES, AND HOMOLOGOUS TO A HERPESVIRUS SAIMIRI GENE, The Journal of immunology, 150(12), 1993, pp. 5445-5456
To detect novel molecules involved in immune functions, a subtracted c
DNA library between closely related murine lymphoid cells was prepared
using improved technology. Differential screening of this library yie
lded several clones with a very restricted tissue specificity, includi
ng one that we named CTLA-8. CTLA-8 transcripts could be detected only
in T cell hybridoma clones related to the one used to prepare the lib
rary. Southern blots showed that the CTLA-8 gene was single copy in mi
ce, rats, and humans. By radioactive in situ hybridization, the CTLA-8
gene was mapped at a single site on mouse chromosome 1 A and human ch
romosome 2q31, in a known interspecific syntenic region. The CTLA-8 cD
NA sequence indicated the presence, in the 3'-untranslated region of t
he mRNA, of AU-rich repeats previously found in the mRNA of various cy
tokines, growth factors, and oncogenes. The CTLA-8 cDNA contained an o
pen reading frame encoding a putative protein of 150 amino acids. This
protein was 57% homologous to the putative protein encoded by the ORF
13 gene of herpesvirus Saimiri, a T lymphotropic virus. These findings
are discussed in the context of other genes of this herpesvirus homol
ogous to known immunologically active molecules. More generally, CTLA-
8 may belong to the growing set of virus-captured functionally importa
nt cellular genes related to the immune system or to cell death and ce
ll survival.