McDowall J S, Rose A
Mol Gen Genet. 1997 Jun;255(1):78-95. doi: 10.1007/s004380050476.
Lethal mutations in the 0.5 map unit region between dpy-5 and bli-4 on chromosome I in Caenorhabditis elegans were serially rescued using cosmid-containing transgenic strains. All the lethal mutations analyzed came from a set of 495 EMS-induced, sDp2-rescued lethals described previously. Germline transformation with cosmid DNA was used to create 25 transgenic strains bearing heritable extrachromosomal arrays. These arrays were used as small duplications for the fine-scale mapping of essential genes, via the rescue of lethal mutations. Lethal mutations in 13 essential genes have been phenotypically rescued, allowing the alignment of the genetic and physical maps in this region. Extrachromosomal arrays were found to be transmitted 2- to 7-fold less frequently in oocytes than in hermaphrodite sperm for 12 of the 16 arrays that were examined. Three of these strains showed a subsequent 4- to 13-fold increase in array stability in oocytes. This phenomenon may be influenced by cosmid sequences. Early mitotic loss of the arrays was observed in all 17 transgenic strains examined, suggesting that loss of the array can occur at any time during development when cell divisions are occurring. As a result of this work, 13 of the essential loci positioned between dpy-5 and bli-4 are anchored to the physical map, thereby providing links between the physical and genetic maps on average every 85 kb.
利用含黏粒的转基因品系，对秀丽隐杆线虫I号染色体上dpy - 5和bli - 4之间0.5个图距单位区域内的致死突变进行了连续拯救。所有分析的致死突变均来自先前描述的一组495个经EMS诱导、sDp2拯救的致死突变。用黏粒DNA进行种系转化，创建了25个带有可遗传的染色体外阵列的转基因品系。这些阵列被用作小重复片段，通过拯救致死突变对必需基因进行精细定位。13个必需基因中的致死突变已在表型上得到拯救，从而实现了该区域遗传图谱和物理图谱的比对。在所检测的16个阵列中的12个中，发现染色体外阵列在卵母细胞中的传递频率比在雌雄同体精子中低2至7倍。其中三个品系显示随后卵母细胞中阵列稳定性增加了4至13倍。这种现象可能受黏粒序列影响。在所有检测的17个转基因品系中均观察到阵列在有丝分裂早期丢失，这表明在发育过程中细胞分裂发生时，阵列随时可能丢失。这项工作的结果是，位于dpy - 5和bli - 4之间的13个必需基因座被锚定到物理图谱上，从而平均每85 kb在物理图谱和遗传图谱之间建立联系。
