CTLA-8, cloned from an activated T cell, bearing AU-rich messenger RNA instability sequences, and homologous to a herpesvirus saimiri gene.
To detect novel molecules involved in immune functions, a subtracted cDNA library between closely related murine lymphoid cells was prepared using improved technology. Differential screening of this library yielded several clones with a very restricted tissue specificity, including 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 library. Southern blots showed that the CTLA-8 gene was single copy in mice, rats, and humans. By radioactive in situ hybridization, the CTLA-8 gene was mapped at a single site on mouse chromosome 1A and human chromosome 2q31, in a known interspecific syntenic region. The CTLA-8 cDNA sequence indicated the presence, in the 3'-untranslated region of the mRNA, of AU-rich repeats previously found in the mRNA of various cytokines, growth factors, and oncogenes. The CTLA-8 cDNA contained an open reading frame encoding a putative protein of 150 amino acids. This protein was 57% homologous to the putative protein encoded by the ORF13 gene of herpesvirus Saimiri, a T lymphotropic virus. These findings are discussed in the context of other genes of this herpesvirus homologous to known immunologically active molecules. More generally, CTLA-8 may belong to the growing set of virus-captured functionally important cellular genes related to the immune system or to cell death and cell survival.
Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, France.
E
E
Rouvier
M F
MF
Luciani
M G
MG
Mattéi
F
F
Denizot
P
P
Golstein
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016923:Cell Death; D004247:DNA / Q000302:isolation & purification*; D005814:Genes, Viral; D006567:Herpesvirus 2, Saimiriine / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012333:RNA, Messenger / Q000032:analysis* / Q000737:chemistry; D012091:Repetitive Sequences, Nucleic Acid; D013601:T-Lymphocytes / Q000737:chemistry*
D012333:RNA, Messenger; D004247:DNA