Rivella S, Tamanini F, Bione S, Mancini M, Herman G, Chatterjee A, Maestrini E, Toniolo D
Istituto di Genetica Biochimica ed Evoluzionistica, CNR, Pavia, Italy.
Genomics. 1995 Aug 10;28(3):377-82. doi: 10.1006/geno.1995.1164.
The transcriptional organization of the region of the mouse X chromosome between the G6pd and the Fln1 genes was studied in detail, and it was compared with the syntenic region of the human chromosome. A cosmid contig of 250 kb was constructed by screening mouse cosmid libraries with probes for human genes and with whole cosmids. Overlapping cosmids were aligned by comparing EcoRI and rare-cutter restriction enzyme digestions. The gene order and the orientation of transcription were determined by hybridization with fragments from the 5' and 3' moieties of each cDNA. Our work demonstrates that all of the new genes identified in human are present in the mouse. The size of the region, 250 kb, is also very similar, as are gene order and gene organization: the transcriptional organization in "domains" described in human is found to be identical in the mouse. The major difference detected is the much lower content in rare-cutter restriction sites, which is related to the lower G+C and CpG content of mouse DNA. The very high conservation that we have described suggests that a potent selective pressure has contributed to such conservation of gene organization.
对小鼠X染色体上位于G6pd基因和Fln1基因之间区域的转录组织进行了详细研究，并将其与人类染色体的同区域进行了比较。通过用人类基因探针和完整的黏粒筛选小鼠黏粒文库，构建了一个250 kb的黏粒重叠群。通过比较EcoRI和稀有切割限制酶消化产物，对重叠的黏粒进行了比对。通过与每个cDNA的5'和3'部分的片段杂交，确定了基因顺序和转录方向。我们的研究表明，在人类中鉴定出的所有新基因在小鼠中都存在。该区域的大小为250 kb，也非常相似，基因顺序和基因组织也是如此：在人类中描述的“结构域”中的转录组织在小鼠中被发现是相同的。检测到的主要差异是稀有切割限制位点的含量低得多，这与小鼠DNA中较低的G+C和CpG含量有关。我们所描述的高度保守性表明，强大的选择压力促成了基因组织的这种保守性。
