Epigenetic regulation of geneexpressions via methylation of histone tail during tissue regeneration

半代谢昆虫，如蟋蟀，具有显著的再生能力。当蟋蟀若虫失去部分腿时，失去的部分腿由胚体再生，胚体是一群去分化的增殖细胞。在囊胚细胞中，编码组蛋白H3 27赖氨酸残基甲基转移酶（H3K27）的zeste增强子（E(z)）和编码组蛋白H3K27甲基化去甲基化酶的Utx等几个表观遗传蛋白基因的表达与分化细胞相比上调。我们对E(z)a和Utx进行了RNAi。E(z)（RNAi）和Utx（RNAi）蟋蟀稚虫再生腿形态异常。几个腿模式基因在E(z)（RNAi）蟋蟀再生腿中异位表达，而在Utx（RNAi）蟋蟀中表达减少。组蛋白H3K27的甲基化在E(z)（RNAi）和Utx（RNAi）蟋蟀中分别减少和增加，这表明通过组蛋白H3K27的甲基化对腿部模式基因表达的表观遗传调控参与了腿部再生过程中的重塑过程。

Hemimetabolous insects, such as cricket Gryllus bimaculatus, have remarkable regenerative capacity. When cricket nymph loses a part of leg, the lost part of leg is regenerated from blastema, which is a population of dedifferentiated proliferating cells. In the blastema cells, expressions of several epigenetic protein genes including Enhancer of zeste(E(z)), which encodes methyltransferase on histone H3 27th lysine residue (H3K27), and Utx, which encodes demethylase for methylated histone H3K27, were upregulated compared with differentiated cells. We performed RNAi against E(z)a n d Utx. Morphologies of regeneration legs of E(z)(RNAi) and Utx(RNAi) cricket nymphs were abnormal. Several leg patterning genes were ectopically expressed in regeneration leg of E(z)(RNAi) cricket and were diminished in Utx(RNAi) cricket. Methylation of histone H3K27 was diminished and increased in E(z)(RNAi) and Utx(RNAi) crickets, respectively, suggesting that epigenetic regulation of leg patterning genes expressions via methylation of histone H3K27 is involved in repatterning process during leg regeneration.