Yen C H, Matsuda Y, Chapman V M, Elliott R W
Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, New York State Department of Health, Buffalo 14263, USA.
Mamm Genome. 1995 Feb;6(2):96-102. doi: 10.1007/BF00303251.
A lambda clone of mouse DNA containing a short array of telomere hexamers has been localized by FISH to a region close to the centromere of Chromosome (Chr) 6. Amplification of DNA with primers flanking an SSR showed that most inbred strains carry one of two alleles, although five other alleles were found among the inbred strains and 11 other alleles were found in wild-derived mice. Analysis of the DNA from four Robertsonian translocations suggests that the amplified sequence is still present in these chromosomes. The finding of two fragments associated with the Sig mutant suggests that the clone lies within a congenic region created when the mutant, obtained in a (C3H x 101)F1, was backcrossed to C57BL/6J. This region might include all or part of the centromere. Comparison of the segregation of the amplification product with the segregation of centromeric heterochromatin in an interspecies backcross, (C57BL/6 x M. spretus)F1 x M. spretus, (BSS) shows 1/72 recombinants with the centromeric heterochromatin, while 1/62 recombinants occurred in a BSB backcross. Analysis of other loci at the proximal end of Chr 6 gives the combined map Hc6-0.73-D6Mit86-0.73-D6Rp2-2.2-D6Mitl-2.2-Wn t2-3.0-Cpa. Data from a third cross show that Cola2 lies between D6Mit82 and D6Rp2. The portion of the telomere array, Tel-rs3, that has been sequenced contains only 13/31 repeats of the consensus sequence. A variety of sequence changes from the consensus hexamer suggests that this array has been removed for a long time from evolutionary pressures to retain the TTAGGG sequence.
一个包含短串联端粒六聚体的小鼠DNAλ克隆已通过荧光原位杂交（FISH）定位到靠近6号染色体（Chr）着丝粒的区域。用侧翼于简单序列重复（SSR）的引物扩增DNA表明，大多数近交系携带两个等位基因中的一个，不过在近交系中还发现了其他五个等位基因，在野生衍生小鼠中发现了另外11个等位基因。对四个罗伯逊易位的DNA分析表明，扩增序列仍存在于这些染色体中。与Sig突变体相关的两个片段的发现表明，该克隆位于一个同源区域内，该同源区域是在（C3H×101）F1中获得的突变体与C57BL/6J回交时产生的。该区域可能包括全部或部分着丝粒。在种间回交（C57BL/6×M. spretus）F1×M. spretus（BSS）中，扩增产物的分离与着丝粒异染色质的分离比较显示，与着丝粒异染色质有1/72的重组体，而在BSB回交中有1/62的重组体。对6号染色体近端其他位点的分析给出了组合图谱Hc6 - 0.73 - D6Mit86 - 0.73 - D6Rp2 - 2.2 - D6Mit1 - 2.2 - Wnt2 - 3.0 - Cpa。第三次杂交的数据表明，Cola2位于D6Mit82和D6Rp2之间。已测序的端粒阵列部分Tel - rs3仅包含共有序列的13/31个重复。与共有六聚体相比的各种序列变化表明，该阵列已长期脱离保留TTAGGG序列所需的进化压力。
