Shipley J M, Clark J, Crew A J, Birdsall S, Rocques P J, Gill S, Chelly J, Monaco A P, Abe S, Gusterson B A
Section of Cell Biology and Experimental Pathology, Institute of Cancer Research, Sutton, Surrey, UK.
Oncogene. 1994 May;9(5):1447-53.
A high proportion of synovial sarcomas contain the reciprocal translocation t(X;18)(p11.2;q11.2). We have previously localized the breakpoint on the X chromosome between the X chromosome marker DXS255 and an ornithine aminotransferase (OAT) pseudogene region designated OATL2. Subsequently by fluorescence in situ hybridization (FISH) we provided evidence that YACs corresponding to the OATL2 locus spanned the break-point. In order to confirm the position of this breakpoint cosmids corresponding to the OATL2 region were isolated. Most of these cosmids mapped to four cosmid contigs designated C1-C4. Analysis of two contigs, C1- and C4, using FISH established that in four of six synovial sarcomas examined the breakpoint occurs between these two contigs: C1 lies distal to the break-point while C4 is proximal. In contrast we provide evidence that the breakpoint in the remaining two tumours mapped to a second pseudogene region called OATL1 that is telomeric to the OATL2 locus. This heterogeneity of the breakpoint position on the X chromosome explains why in previous mapping studies there have been discrepancies between the results obtained by different laboratories.
高比例的滑膜肉瘤含有相互易位t(X;18)(p11.2;q11.2)。我们先前已将X染色体上的断点定位在X染色体标记DXS255与一个指定为OATL2的鸟氨酸转氨酶（OAT）假基因区域之间。随后通过荧光原位杂交（FISH），我们提供了证据表明与OATL2基因座对应的酵母人工染色体（YAC）跨越了断点。为了确认该断点的位置，分离了与OATL2区域对应的黏粒。这些黏粒中的大多数定位于四个指定为C1 - C4的黏粒重叠群。使用FISH对两个重叠群C1和C4进行分析表明，在所检查的六个滑膜肉瘤中的四个中，断点发生在这两个重叠群之间：C1位于断点的远端，而C4位于近端。相比之下，我们提供的证据表明，其余两个肿瘤中的断点定位于一个称为OATL1的第二个假基因区域，该区域位于OATL2基因座的端粒侧。X染色体上断点位置的这种异质性解释了为什么在先前的定位研究中，不同实验室获得的结果之间存在差异。
