REARRANGEMENTS OF HIGHLY POLYMORPHIC REGIONS NEAR TELOMERES OF SACCHAROMYCES-CEREVISIAE
REARRANGEMENTS OF HIGHLY POLYMORPHIC REGIONS NEAR TELOMERES OF SACCHAROMYCES-CEREVISIAE
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DOI：
10.1128/mcb.4.11.2509
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发表时间：
1984-01-01
影响因子：
5.3
通讯作者：
HABER, JE
中科院分区：
文献类型：
--
作者：
HOROWITZ, H;THORBURN, P;HABER, JE
在各种实验室酵母菌株中检查了端粒区域的有丝分裂和减数分裂特性。使用衍生自克隆的酵母端粒的序列（Y探针），发现酿酒酵母的各种菌株显示出限制性内切核酸酶片段长度的广泛多态性。端粒片段长度的一些变化似乎受到少数基因的控制。当用核酸内切酶 KpnI 消化来自不同菌株的 DNA 时，发现几乎所有与 Y 探针同源的片段都有不同的大小。不同菌株中的片段模式差异极大，多态性程度高于含有可移动 TY1 元件的片段。对来自许多不同 Y 同源 KpnI 片段杂合的二倍体的单倍体减数分裂分离体的四分体分析表明，它们中的大多数表现出孟德尔（2:0）分离。这些片段中只有一小部分显示出同一染色体末端简单等位基因变异所预期的专性 2:2 亲本分离。从这些片段的分离可以得出结论，一些酵母端粒缺乏Y同源序列，并且含有Y同源序列的染色体臂在不同酵母菌株之间是不同的。酵母端粒附近的区域经常发生重排。在来自 3 个不同二倍体的 8 个四分体中，发现了 3 个似乎在减数分裂过程中出现的新 Y 同源限制片段。在所有 3 个案例中，新片段的出现都伴随着另一条带的丢失。在其中一个案例中，导致新片段的重排出现在同基因二倍体中，其中两条同源染色体应该是相同的。在这些四分体中还发现了涉及端粒区域的明显减数分裂基因转换和有丝分裂重组的例子。
The mitotic and meiotic properties of telomeric regions were examined in various laboratory strains of yeast. Using a sequence (Y probe) derived from a cloned yeast telomere various strains of S. cerevisiae were found to show extensive polymorphisms of restriction endonuclease fragment length. Some of the variation in the lengths of telomeric fragments appears to be under the control of a small number of genes. When DNA from various strains was digested with endonuclease KpnI, nearly all of the fragments homologous to the Y probe were found to be of different size. The pattern of fragments in different strains was extremely variable, with a greater degree of polymorphism than that observed for fragments containing the mobile TY1 element. Tetrad analysis of haploid meiotic segregants from diploids heterozygous for many different Y-homologous KpnI fragments revealed that most of them exhibited Mendelian (2:0) segregation. Only a small proportion of these fragments displayed the obligate 2:2 parental segregation expected of simple allelic variants at the same chromosome end. From the segregations of these fragments, it was concluded that some yeast telomeres lack a Y-homologous sequence and that the chromosome arms containing a Y-homologous sequence are different among various yeast strains. Regions near yeast telomeres frequently undergo rearrangement. Among 8 tetrads from 3 different diploids, 3 novel Y-homologous restriction fragments that appear to have arisen during meiosis were found. In all 3 cases, the appearance of a new fragment was accompanied by the loss of another band. In 1 of these cases, the rearrangement leading to a novel fragment arose in an isogenic diploid, in which both homologous chromosomes should have been identical. Examples of apparent meiotic gene conversions and mitotic recombination involving telomeric regions were also found among these tetrads.