LONG-RANGE ORGANIZATION OF REITERATED SEQUENCES, INCLUDING THE SSX1 CDNA, AT THE OATL1 CLUSTER IN XP11.23

Analysis of four YACs at the OATL1 locus was undertaken to determine t he organization of locally repeated sequences within the OATL1 cluster . A restriction map of ICRFy900C0874, a 600-kb YAC, was constructed us ing a range of rare-cutting enzymes. Several markers were isolated fro m the OATL1 cluster, and the YAC map was used for their localization. Markers are shown to be reiterated within the OATL1 cluster, and fine- scale mapping has identified the accurate map position and organizatio n of these repeated sequences within a 275-kb interval. The SSX1 gene involved in synovial sarcoma tumorigenesis and localized at the OATL1 cluster is also shown to be present in a minimum of five copies, all o f which map to the aforementioned region. Several markers generated in this study have homologous counterparts at OATL2; they have been util ized to delimit the duplicated region at the OATL clusters. Although i nstability of one of the OATL1 YACs, ICRFy900F0501, has precluded a pr ecise sizing of this interval, it has been possible to place an upper limit of 520 kb on this region of duplication. (C) 1995 Academic Press , Inc.