Altering a gene involved in nuclear distribution increases the repeat-induced point mutation process in the fungus Podospora anserina
Altering a gene involved in nuclear distribution increases the repeat-induced point mutation process in the fungus Podospora anserina
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DOI：
10.1534/genetics.167.1.151
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发表时间：
2004-05-01
期刊：
影响因子：
3.3
通讯作者：
Arnaise, S
中科院分区：
文献类型：
--
作者：
Bouhouche, K;Zickler, D;Arnaise, S
重复诱导点突变（RIP）是一种依赖同源性的基因沉默机制，它会在重复的DNA片段中引入C:G到T:A的转换。顺式重复序列也可能受到另一种称为减数分裂前重组（PR）的机制的影响。这两种机制在一些丝状真菌（例如粗糙脉孢菌和柄孢壳菌）的有性生殖周期中都起作用。在有性生殖周期中，几个发育步骤需要精确的细胞核移动和定位，但RIP、PR和细胞核分布之间的联系尚未建立。先前的研究已经分离出了ami1，它是构巢曲霉apsA基因在柄孢壳菌中的直系同源基因，对细胞核定位是必需的。我们在此表明，ami1在有性生殖周期中参与细胞核分布，并且ami1的改变会延迟子实体的发育。我们还证明ami1的改变会影响有性生殖周期中转基因功能的丧失。在ami1突变体杂交中，转基因的遗传连锁多拷贝受RIP和PR的影响比在野生型杂交中更为频繁。我们的结果表明，ami1突变体在RIP和PR期间的发育减缓增加了对重复检测系统的暴露时间，从而增加了RIP和PR的频率。
Repeat-induced point mutation (RIP) is a homology-dependent gene-silencing mechanism that introduces C:G-to-T:A transitions in duplicated DNA segments. Cis-duplicated sequences can also be affected by another mechanism called premeiotic recombination (PR). Both are active over the sexual cycle of some filamentous fungi, e.g., Neurospora crassa and Podospora anserina. During the sexual cycle, several developmental steps require precise nuclear movement and positioning, but connections between RIP, PR, and nuclear distributions have not yet been established. Previous work has led to the isolation of ami1, the P. anserina ortholog of the Aspergillus nidulans apsA gene, which is required for nuclear positioning. We show here that ami1 is involved in nuclear distribution during the sexual cycle and that alteration of ami1 delays the fruiting-body development. We also demonstrate that ami1 alteration affects loss of transgene functions during the sexual cycle. Genetically linked multiple copies of transgenes are affected by RIP and PR much more frequently in an ami1 mutant cross than in a wild-type cross. Our results suggest that the developmental slowdown of the ami1 mutant during the period of RIP and PR increases time exposure to the duplication detection system and thus increases the frequency of RIP and PR.