Unitat de Biologia Cel·lular, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Spain.
Genomics. 2012 Dec;100(6):380-6. doi: 10.1016/j.ygeno.2012.08.007. Epub 2012 Aug 28.
Low-copy repeats (LCRs) constitute 5% of the human genome. LCRs act as substrates for non-allelic homologous recombination (NAHR) leading to genomic structural variation. The aim of this study was to assess the potential of Fiber-FISH for LCRs direct visualization to support investigations of genome architecture within these challenging genomic regions. We describe a set of Fiber-FISH experiments designed for the study of the LCR22-2. This LCR is involved in recurrent reorganizations causing different genomic disorders. Four fosmid clones covering the entire length of the LCR22-2 and two single-copy BAC-clones, delimiting the LCR22-2 proximally and distally, were selected. The probes were hybridized in different multiple color combinations on DNA fibers from two karyotypically normal cell lines. We were able to identify three distinct structural haplotypes characterized by differences in copy-number and arrangement of the LCR22-2 genes and pseudogenes. Our results show that Multicolor Fiber-FISH is a viable methodological approach for the analysis of genome organization within complex LCR regions.
低拷贝重复序列（LCRs）占人类基因组的 5%。LCRs 可作为非等位基因同源重组（NAHR）的底物，导致基因组结构变异。本研究旨在评估 Fiber-FISH 用于 LCRs 直接可视化的潜力，以支持在这些具有挑战性的基因组区域内研究基因组结构。我们描述了一系列 Fiber-FISH 实验，旨在研究 LCR22-2。该 LCR 参与导致不同基因组疾病的反复重排。选择了四个覆盖 LCR22-2 全长的 fosmid 克隆和两个单拷贝 BAC-克隆，分别近端和远端限定 LCR22-2。将探针在来自两个核型正常细胞系的 DNA 纤维上以不同的多色组合杂交。我们能够鉴定出三个不同的结构单倍型，其特征是 LCR22-2 基因和假基因的拷贝数和排列存在差异。我们的结果表明，多色 Fiber-FISH 是分析复杂 LCR 区域内基因组组织的可行方法。
