Schechtman M G
Biology Department, Syracuse University, NY 13244.
Gene. 1990 Apr 16;88(2):159-65. doi: 10.1016/0378-1119(90)90027-o.
The nucleotide sequence of the telomere at the right end of linkage group V (VR) in the standard OR23-IV-A strain of the filamentous fungus, Neurospora crassa, reveals the following features. At the chromosome terminus, tandem repeats of the hexanucleotide TTAGGG are present. Immediately centromere-proximal to the simple sequence repeat is a more complex element called Pogo that is reiterated 5-10 times in the genomes of various Neurospora strains. The element possesses several features characteristic of a transposable element: direct repeats of 318 bp flank the element, there is a long internal open reading frame (ORF), and a 3-bp duplication is found at its borders. However, Pogo has other structural features that are more difficult to reconcile with the standard model of a transposable element. A second telomere from Neurospora was also cloned by screening a genomic lambda library with a synthetic oligodeoxyribonucleotide homologous to the simple sequence repeats. This telomere is entirely non-homologous with the VR telomere except for the TTAGGG repeats, has no associated copy of Pogo, and has no nearby ORFs. There are no long stretches of TTAGGG repeats present in the Neurospora genome at non-telomeric sites.
在丝状真菌粗糙脉孢菌的标准OR23-IV-A菌株中，连锁群V（VR）右端端粒的核苷酸序列显示出以下特征。在染色体末端，存在六核苷酸TTAGGG的串联重复序列。紧挨着简单序列重复序列且靠近着丝粒的是一个更复杂的元件，称为Pogo，它在各种脉孢菌菌株的基因组中重复出现5至10次。该元件具有转座元件的几个特征：318 bp的正向重复序列位于元件两侧，有一个长的内部开放阅读框（ORF），并且在其边界处发现了一个3 bp的重复序列。然而，Pogo还有其他结构特征，这些特征更难以与转座元件的标准模型相协调。通过用与简单序列重复序列同源的合成寡脱氧核糖核苷酸筛选基因组λ文库，还克隆了来自脉孢菌的另一个端粒。除了TTAGGG重复序列外，这个端粒与VR端粒完全不同源，没有相关的Pogo拷贝，也没有附近的ORF。在脉孢菌基因组的非端粒位点不存在长片段的TTAGGG重复序列。
