Genomic sequence and transcriptional profile of the boundary between pericentromeric satellites and genes on human chromosome arm 10p
Genomic sequence and transcriptional profile of the boundary between pericentromeric satellites and genes on human chromosome arm 10p
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DOI：
10.1101/gr.644503
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发表时间：
2003-02-01
期刊：
影响因子：
7
通讯作者：
Jackson, MS
中科院分区：
文献类型：
--
作者：
Guy, J;Hearn, T;Jackson, MS
如果我们要了解着丝粒周围不稳定性在疾病中的作用，以及在基因和核型进化中的作用，就需要从人类染色体的高度重复的着丝粒周围区域获得连续的完整序列。在这里，我们构建了一个BAC重叠群，跨越了从近着丝粒卫星到人类10号染色体短臂上基因的过渡，并使用它来生成1.4 Mb的完成基因组序列。结合RT-PCR、计算机基因预测和旁系分析，我们可以识别序列中的两个结构域。近端600 kb由富含卫星的近着丝粒重复DNA组成，该DNA是转录贫乏的，仅含有三个未剪接的转录本。相反，远端850 kb包含4个已知基因（ZNF 248、ZNF 25、ZNF 33 A和ZNF 37 A）和多达32个功能未知的额外转录本。这个远端区域也包含了该序列内8个染色体内重复中的7个，包括产生ZNF 33 A和ZNF 33 B的类似于250-kb重复的p臂拷贝。通过对重复的ZNF 33基因的直系同源物进行测序，我们已经确定ZNF 33 A在对DNA结合至关重要的残基上发生了显着差异，但ZNF 33 B却没有，这表明ZNF 33 B仍然受到祖先基因功能选择的限制。这些结果提供了进一步的证据内的染色体内重复的基因形成，但表明，最近在这个着丝粒染色体间重复涉及转录惰性，卫星丰富的DNA，这是可能是异染色质。这表明，由这些染色体间事件形成的任何新的基因结构都需要重新定位到更开放的染色质环境中才能表达。
Contiguous finished sequence from highly duplicated pericentromeric regions of human chromosomes is needed if we are to understand the role of pericentromeric instability in disease, and in gene and karyotype evolution. Here, we have constructed a BAC contig spanning the transition from pericentromeric satellites to genes on the short arm of human chromosome 10, and used this to generate 1.4 Mb of finished genomic sequence. Combining RT-PCR, in silico gene prediction, and paralogy analysis, we can identify two domains within the sequence. The proximal 600 kb consists of satellite-rich pericentromerically duplicated DNA which is transcript poor, containing only three unspliced transcripts. In contrast, the distal 850 kb contains four known genes (ZNF248, ZNF25, ZNF33A, and ZNF37A) and up to 32 additional transcripts of unknown function. This distal region also contains seven out of the eight intrachromosomal duplications within the sequence, including the p arm copy of the similar to250-kb duplication which gave rise to ZNF33A and ZNF33B. By sequencing orthologs of the duplicated ZNF33 genes we have established that ZNF33A has diverged significantly at residues critical for DNA binding but ZNF33B has not, indicating that ZNF33B has remained constrained by selection for ancestral gene function. These results provide further evidence of gene formation within intrachromosomal duplications, but indicate that recent interchromosomal duplications at this centromere have involved transcriptionally inert, satellite rich DNA, which is likely to be heterochromatic. This suggests that any novel gene structures formed by these interchromosomal events would require relocation to a more open chromatin environment to be expressed.