CHARACTERIZATION OF THE MOUSE TCRA-V22 GENE SUBFAMILY

T-cell receptors (Tcrs) of higher organisms play a key role in the spe cific recognition of self and non-self molecules in the immune system. The large number of Tcr variable (V) genes have been organized into V gene subfamilies according to their sequence similarity at the nucleo tide and amino acid level. We cloned and characterized four new member s of the Tcra-V22 gene subfamily at the genomic level using a simple a nd sensitive technique that can rapidly clone members of any multi-mem ber gene family. Sequence analysis reveals that the four Tcra-V22 gene subfamily members have more than 98% sequence similarity in their cod ing regions, at the nucleotide and amino acid levels. However, the int ron between the leader and the coding region varies up to 7% between m embers of the Tcra-V22 gene subfamily. Comparison of the multimember T cra-V22 gene subfamily with other multi-member Tcra-V gene subfamilies (V2, V8, and VII), shows that Tcra-V22 is unique in that it has multi ple members with nearly identical amino acid sequence and which are no t inherently pseudogenes. Sequence similarity analysis of the Tcra-V22 subfamily with the prototypes of all other Tcra-V subfamilies reveale d that the Tcra-V22 subfamily has the closest sequence similarity to t hat of Tcra-V18 (77% at the nucleotide level and 71% at the amino acid level).