IDENTIFICATION OF NOVEL GENES, SYT AND SSX, INVOLVED IN THE T(X18)(P11.2Q11.2) TRANSLOCATION FOUND IN HUMAN SYNOVIAL SARCOMA

Human synovial sarcomas contain a recurrent and specific chromosomal translocation t(X;18)(p11.2;q11.2). By screening a synovial sarcoma cDNA library with a yeast artificial chromosome spanning the X chromosome breakpoint, we have indentified a hybrid transcript that contains 5' sequences (designated SYT) mapping to chromosome 18 and 3' sequences (designated SSX) mapping to chromosome X. An SM probe detected genomic rearrangements in 10/13 synovial sarcomas. Sequencing of cDNA clones shows that the normal SM gene encodes a protein rich in glutamine, proline and glycine, and indicates that in synovial sarcoma rearrangement of the SYT gene results in the formation of an STT-SSX fusion protein. Both SYT and SSX failed to exhibit significant homology to known gene sequences.