Touchman J W, Bouffard G G, Weintraub L A, Idol J R, Wang L, Robbins C M, Nussbaum J C, Lovett M, Green E D
Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Genome Res. 1997 Mar;7(3):281-92. doi: 10.1101/gr.7.3.281.
The establishment and mapping of gene-specific DNA sequences greatly complement the ongoing efforts to map and sequence all human chromosomes. To facilitate our studies of human chromosome 7, we have generated and analyzed 2006 expressed-sequence tags (ESTs) derived from a collection of direct selection cDNA libraries that are highly enriched for human chromosome 7 gene sequences. Similarity searches indicate that approximately two-thirds of the ESTs are not represented by sequences in the public databases, including those in dbEST. In addition, a large fraction (68%) of the ESTs do not have redundant or overlapping sequences within our collection. Human DNA-specific sequence-tagged sites (STSs) have been developed from 190 of the ESTs. Remarkably, 180 (96%) of these STSs map to chromosome 7, demonstrating the robustness of chromosome enrichment in constructing the direct selection cDNA libraries. Thus far, 140 of these EST-specific STSs have been assigned unequivocally to YAC contigs that are distributed across the chromosome. Together, these studies provide > 2000 ESTs highly enriched for chromosome 7 gene sequences, 180 new chromosome 7 STSs corresponding to ESTs, and a definitive demonstration of the ability to enrich for chromosome-specific cDNAs by direct selection. Furthermore, the libraries, sequence data, and mapping information will contribute to the construction of a chromosome 7 transcript map.
基因特异性DNA序列的建立与定位极大地补充了正在进行的人类所有染色体的定位与测序工作。为了促进我们对人类7号染色体的研究，我们生成并分析了2006个表达序列标签（EST），这些EST来自一组直接选择的cDNA文库，该文库高度富集了人类7号染色体基因序列。相似性搜索表明，大约三分之二的EST在公共数据库（包括dbEST中的序列）中没有对应的序列。此外，很大一部分（68%）的EST在我们的文库中没有冗余或重叠序列。已从190个EST中开发出人类DNA特异性序列标签位点（STS）。值得注意的是，其中180个（96%）STS定位于7号染色体，这证明了在构建直接选择cDNA文库时染色体富集的稳健性。到目前为止，这些EST特异性STS中的140个已明确分配到分布在该染色体上的酵母人工染色体（YAC）重叠群中。总之，这些研究提供了2000多个高度富集7号染色体基因序列的EST、180个与EST对应的新的7号染色体STS，以及通过直接选择富集染色体特异性cDNA能力的明确证明。此外，这些文库、序列数据和定位信息将有助于构建7号染色体转录图谱。
