Schechtman M G
Department of Biology, Syracuse University, New York 13244.
Mol Cell Biol. 1987 Sep;7(9):3168-77. doi: 10.1128/mcb.7.9.3168-3177.1987.
The most distal known gene on Neurospora crassa linkage group VR, his-6, was cloned. A genomic walk resulted in isolation of the telomere at VR. It was obtained from a library in which the endmost nucleotides of the chromosome had not been removed by nuclease treatment before being cloned, and mapping indicates that the entire chromosome end has probably been cloned. Sequences homologous to the terminal 2.5 kilobases of DNA from VR from these Oak Ridge N. crassa strains are found at other sites in the genome. To characterize these sites, I crossed an Oak Ridge-derived his-6 strain with a wild-type strain of different genetic background (Mauriceville) and characterized the hybridization patterns seen in the progeny. It appears that the sequences homologous to the VR terminus are found at genetically different sites in the two parental strains, and no hybridization to the VR telomere from Mauriceville was detected. The other genomic copies identified in the Oak Ridge parent were not telomeres. I suggest that any repeating sequence blocks found immediately adjacent to the VR terminus in Oak Ridge strains must be small and that the repeating element identified in that background may be an N. crassa transposable element integrated near the the chromosome end at VR.
克隆了粗糙脉孢菌连锁群VR上已知最远端的基因his-6。通过基因组步移法分离出了VR的端粒。它是从一个文库中获得的，在该文库中，染色体的最末端核苷酸在克隆前未经过核酸酶处理，并且定位表明整个染色体末端可能已被克隆。在这些橡树岭粗糙脉孢菌菌株中，与来自VR的DNA末端2.5千碱基同源的序列在基因组的其他位点也有发现。为了表征这些位点，我将一株来自橡树岭的his-6菌株与具有不同遗传背景的野生型菌株（莫里斯维尔）进行杂交，并对后代中观察到的杂交模式进行了表征。似乎与VR末端同源的序列在两个亲本菌株的基因不同位点被发现，并且未检测到与来自莫里斯维尔的VR端粒的杂交。在橡树岭亲本中鉴定出的其他基因组拷贝不是端粒。我认为，在橡树岭菌株中紧邻VR末端发现的任何重复序列块一定很小，并且在该背景中鉴定出的重复元件可能是一个整合在VR染色体末端附近的粗糙脉孢菌转座元件。
