High frequency intragenic recombination during macronuclear development in Tetrahymena thermophila restores the wild-type SerH1 gene.-猫眼课题宝

嗜热四膜虫大核发育过程中的高频基因内重组恢复了野生型 SerH1 基因。

DOI：

发表时间：

1998

期刊：

Genetics

影响因子：

3.3

通讯作者：

中科院分区：

生物学2区

文献类型：

作者：

J. Deák;F. P. Doerder

纤毛虫的大核发育以遗传物质的广泛重排为特征，包括序列消除、染色体断裂和端粒增加。基因内重组是一种相对罕见但在进化上具有重要意义的现象，它发生在多种生物的有丝分裂和减数分裂中。在这里，我们发现在嗜热四膜虫发育中的无丝分裂大核中发生了大约30%的高频基因内重组。这种重组发生在被726个核苷酸隔开的两个无义转换突变之间，可重复地恢复SerH1表面蛋白基因的野生型表达，从而模仿反式杂合子中的互补。重组必须被认为是大核发育的一个潜在的重要方面，产生生发微核中不存在的基因组合。

Macronuclear development in ciliates is characterized by extensive rearrangement of genetic material, including sequence elimination, chromosome fragmentation and telomere addition. Intragenic recombination is a relatively rare, but evolutionarily important phenomenon occurring in mitosis and meiosis in a wide variety of organisms. Here, we show that high frequency intragenic recombination, on the order of 30%, occurs in the developing amitotic macronucleus of the ciliate Tetrahymena thermophila. Such recombination, occurring between two nonsense transition mutations separated by 726 nucleotides, reproducibly restores wild-type expression of the SerH1 surface protein gene, thus mimicking complementation in trans heterozygotes. Recombination must be considered a potentially important aspect of macronuclear development, producing gene combinations not present in the germinal micronucleus.