Recent studies have identified mutations in PHF8, an X-linked gene encoding a JmjC domain-containing protein, as a causal factor for X-linked mental retardation （XLMR） and cleft lip/cleft palate. However, the underl...Recent studies have identified mutations in PHF8, an X-linked gene encoding a JmjC domain-containing protein, as a causal factor for X-linked mental retardation （XLMR） and cleft lip/cleft palate. However, the underlying mechanism is unknown. Here we show that PHF8 is a histone demethylase and coactivator for retinoic acid receptor （RAR）. Although activities for both H3K4me3/2/1 and H3K9me2/1 demethylation were detected in cellularbased assays, reeombinant PHF8 exhibited only H3K9me2/1 demethylase activity in vitro, suggesting that PHF8 is an H3K9me2/1 demethylase whose specificity may be modulated in vivo. Importantly, a mutant PHF8 （phenylalanine at position 279 to serine） identified in the XLMR patients is defective in enzymatie activity, indicating that the loss of histone demethylase activity is causally linked with the onset of disease. In addition, we show that PHF8 binds specifically to H3K4me3/2 peptides via an N-terminal PHD finger domain. Consistent with a role for PHF8 in neuronal differentiation, knockdown of PHF8 in mouse embryonic carcinoma P19 cells impairs RA-induced neuronal differentiation, whereas overexpression of the wild-type but not the F279S mutant PHF8 drives PI9 cells toward neuronal differentiation. Furthermore, we show that PHF8 interacts with RAR~ and functions as a coactivator for RARa. Taken together, our results suggest that histone methylation modulated by PHF8 plays a critical role in neuronal differentiation.展开更多
采用家蚕耐氟品系T6和敏感品系733新组配正反交群体(733新×T6)×733新和733新×(733新×T6),分别记作BC1F和BC1M。基于雌性家蚕染色体不发生交换,用已构建的家蚕SSR连锁图上的标记对耐氟基因(dominant endurangce to f...采用家蚕耐氟品系T6和敏感品系733新组配正反交群体(733新×T6)×733新和733新×(733新×T6),分别记作BC1F和BC1M。基于雌性家蚕染色体不发生交换,用已构建的家蚕SSR连锁图上的标记对耐氟基因(dominant endurangce to fluoride,Def)进行了定位及连锁分析。在28个连锁群上都找到了多态标记,其中只有3个位于12连锁群上的SSR标记与耐氟基因连锁。根据第12连锁群上已有的微卫星序列,寻找其所在的Scaffold上的其它SSR位点,并设计引物,找到一个新的多态性SSR标记。BC1F群中的所有耐氟个体均表现出与(733新×T6)F1相同的杂合型带型,而所有敏感个体带型与亲本733新一致,均为纯合型,说明家蚕耐氟性状是由位于第12连锁群上单个显性主效基因控制的。利用另一个群体BCM构建了耐氟基因的遗传连锁图。展开更多
文摘Recent studies have identified mutations in PHF8, an X-linked gene encoding a JmjC domain-containing protein, as a causal factor for X-linked mental retardation （XLMR） and cleft lip/cleft palate. However, the underlying mechanism is unknown. Here we show that PHF8 is a histone demethylase and coactivator for retinoic acid receptor （RAR）. Although activities for both H3K4me3/2/1 and H3K9me2/1 demethylation were detected in cellularbased assays, reeombinant PHF8 exhibited only H3K9me2/1 demethylase activity in vitro, suggesting that PHF8 is an H3K9me2/1 demethylase whose specificity may be modulated in vivo. Importantly, a mutant PHF8 （phenylalanine at position 279 to serine） identified in the XLMR patients is defective in enzymatie activity, indicating that the loss of histone demethylase activity is causally linked with the onset of disease. In addition, we show that PHF8 binds specifically to H3K4me3/2 peptides via an N-terminal PHD finger domain. Consistent with a role for PHF8 in neuronal differentiation, knockdown of PHF8 in mouse embryonic carcinoma P19 cells impairs RA-induced neuronal differentiation, whereas overexpression of the wild-type but not the F279S mutant PHF8 drives PI9 cells toward neuronal differentiation. Furthermore, we show that PHF8 interacts with RAR~ and functions as a coactivator for RARa. Taken together, our results suggest that histone methylation modulated by PHF8 plays a critical role in neuronal differentiation.
文摘采用家蚕耐氟品系T6和敏感品系733新组配正反交群体(733新×T6)×733新和733新×(733新×T6),分别记作BC1F和BC1M。基于雌性家蚕染色体不发生交换,用已构建的家蚕SSR连锁图上的标记对耐氟基因(dominant endurangce to fluoride,Def)进行了定位及连锁分析。在28个连锁群上都找到了多态标记,其中只有3个位于12连锁群上的SSR标记与耐氟基因连锁。根据第12连锁群上已有的微卫星序列,寻找其所在的Scaffold上的其它SSR位点,并设计引物,找到一个新的多态性SSR标记。BC1F群中的所有耐氟个体均表现出与(733新×T6)F1相同的杂合型带型,而所有敏感个体带型与亲本733新一致,均为纯合型,说明家蚕耐氟性状是由位于第12连锁群上单个显性主效基因控制的。利用另一个群体BCM构建了耐氟基因的遗传连锁图。
