The Chapel Hill hemophilia A dog colony exhibits a factor VIII gene inversion
The Chapel Hill hemophilia A dog colony exhibits a factor VIII gene inversion
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DOI：
10.1073/pnas.192219599
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发表时间：
2002-10-01
影响因子：
11.1
通讯作者：
Morgan, RA
中科院分区：
文献类型：
--
作者：
Lozier, JN;Dutra, A;Morgan, RA
在查佩尔山的因子VIII缺陷犬群中，因子VIII转录物中外显子1-22之后的异常序列（ch 8，犬血友病8，GenBank编号AF 361485）取代了外显子23-26。犬血友病8基因座（ch 8）序列被发现在一个140 kb的正常狗基因组DNA细菌人工染色体（BAC）克隆，完全是外因子VIII基因，但不是在BAC克隆含有因子VIII基因。含有ch 8的BAC克隆还含有F8 A（因子8相关）序列的同源物，其参与导致人类严重血友病A的常见倒位。荧光原位杂交分析表明，外显子1-26通常在Xq 28处从端粒顺序延伸到着丝粒，并且ch 8位于因子VIII基因的端粒。在异常因子VIII转录物末端出现“上游”基因组序列元件（ch 8）表明基因组DNA的倒位用ch 8替换因子VIII外显子22-26。F8 A序列也出现在含有因子VIII序列的重叠正常BAC克隆中。我们假设在犬F8 A因子VIII基因内部和外部的拷贝之间发生了同源重组，就像在人类血友病A中一样。高分辨率荧光原位杂交血友病A狗的DNA揭示了一种模式与这种倒位机制一致。我们还鉴定了F8 A片段的Hindill限制性片段长度多态性，可区分血友病A、携带者和正常狗的DNA。因此，查佩尔山血友病A犬群复制了在患有严重血友病A的人类中常见的因子VIII基因倒位。
In the Chapel Hill colony of factor VIII-deficient dogs, abnormal sequence (ch8, for canine hemophilia 8, GenBank no. AF361485) follows exons 1-22 in the factor VIII transcript in place of exons 23-26. The canine hemophilia 8 locus (ch8) sequence was found in a 140-kb normal dog genomic DNA bacterial artificial chromosome (BAC) clone that was completely outside the factor VIII gene, but not in BAC clones containing the factor VIII gene. The BAC clone that contained ch8 also contained a homologue of F8A (factor 8 associated) sequence, which participates in a common inversion that causes severe hemophilia A in humans. Fluorescence in situ hybridization analysis indicated that exons 1-26 normally proceed sequentially from telomere to centromere at Xq28, and ch8 is telomeric to the factor VIII gene. The appearance of an "upstream" genomic sequence element (ch8) at the end of the aberrant factor VIII transcript suggested that an inversion of genomic DNA replaced factor VIII exons 22-26 with ch8. The F8A sequence appeared also in overlapping normal BAC clones containing factor VIII sequence. We hypothesized that homologous recombination between copies of canine F8A inside and outside the factor VIII gene had occurred, as in human hemophilia A. High-resolution fluorescent in situ hybridization on hemophilia A dog DNA revealed a pattern consistent with this inversion mechanism. We also identified a Hindill restriction fragment length polymorphism of F8A fragments that distinguished hemophilia A, carrier, and normal dogs' DNA. The Chapel Hill hemophilia A dog colony therefore replicates the factor VIII gene inversion commonly seen in humans with severe hemophilia A.