表观遗传学研究的模式生物——粗糙脉孢菌

A Model Organism for Epigenetics Study: Neurospora crassa

丝状真菌粗糙脉孢菌是一种作为遗传学研究的经典模式生物.通过对粗糙脉孢菌5S r RNA基因的组成和在染色体上分布的研究,揭示了丝状真菌中存在的一种基因组防御机制——重复序列诱导的DNA点突变(RIP).通过对发生突变的5S r RNA假基因的研究还发现,粗糙脉孢菌中存在一种重要的表观遗传修饰——DNA甲基化,随后的深入研究使粗糙脉孢菌成为解析DNA甲基化机制的最重要模式生物之一.粗糙脉孢菌基因转化操作引起的营养生长阶段同源基因的沉默(quelling)是由RNAi途径调控的,同时该途径也是调控减数分裂过程中非配对DNA诱发的基因沉默(meiotic silencing)的关键.由于粗糙脉孢菌基因组简单,且存在与高等真核生物相同的DNA甲基化和多种组蛋白的修饰,使其成为今后深入研究组蛋白修饰与染色质重塑等表观遗传现象参与基因表达调控和基因组稳定性维持的重要模式生物之一.

The filamentous fungus Neurospora crassa is a global model for genetic research. The analyses of its 5S RNA genes＇ composition and distribution across the genome revealed the genomic defense system RIP （repeat-induced point mutation）. And by analyzing its mutated 5S RNA pseudogenes, one important epigenetic modification, DNA methylation, was identified. Subsequent research made Neurospora crassa as one of the most extensive model organisms for investigation the mechanism of DNA methylation among the eukaryotes. During its vegetative growth stage, the homologous genes silencing （quelling） caused by transgene was demonstrated to be regulated by RNA interference which was exhibited to play a key role in meiotic silencing. The features of ,Neurospora crassa including its streamlined genome and the same DNA methylation and histone modifications as the higher eukaryotes will make it an important model organism to further research the epigenetic regulation of gene expression and genome stability.