Epigenetic phenomena in filamentous fungi: useful paradigms or repeat-induced confusion?
Epigenetic phenomena in filamentous fungi: useful paradigms or repeat-induced confusion?
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DOI：
10.1016/s0168-9525(97)01201-8
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发表时间：
1997-08
期刊：
影响因子：
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通讯作者：
E. Selker
中科院分区：
文献类型：
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作者：
E. Selker
表观遗传机制可以作为基因组防御系统。在真菌的特殊性细胞的单倍体细胞核中，如脉孢菌属和子囊菌属，重复的基因被超突变、DNA甲基化或两者所沉默。在某些情况下，通过转化引入脉孢菌细胞基因组的DNA也可以通过不涉及DNA配对或甲基化并且似乎是转录后的沉默机制抑制同源基因。转化DNA还可以触发营养细胞中的从头甲基化，然后导致转录沉默。真菌营养细胞中的沉默规则尚未明确，但重复序列似乎特别容易受到这些过程的影响。因此，真菌表现出重复诱导和重复相关的沉默机制。此外，一些天然基因依赖于在双相中的同源配对来进行适当的调节。总之，这些过程应该限制转座因子的增殖，并有助于保护基因组的整体结构。
Epigenetic mechanisms can serve as genome defense systems. In haploid nuclei of special sexual cells of fungi, such as Neurospora and Ascobolus, duplicated genes are silenced by hypermutation, DNA methylation, or both. In some cases, DNA introduced into the genome of Neurospora cells by transformation can also inhibit homologous genes by a silencing mechanism that does not involve DNA pairing or methylation and appears to be post-transcriptional. Transforming DNA can also trigger de novo methylation in vegetative cells, which then causes transcriptional silencing. The rules governing silencing in vegetative cells of fungi are undefined, but repeated sequences seem particularly susceptible to these processes. Thus, fungi exhibit both repeat-induced and repeat-associated silencing mechanisms. Additionally, some native genes depend on homologous pairing in the diplophase for proper regulation. Together, these processes should limit the proliferation of transposable elements and serve to preserve the overall structure of the genome.