Propagation strategy of the double-stranded RNA replicon symbiotically in a rice cell.

我们在许多作物和野生植物中发现了各种双链RNA(DsRNA)。国际病毒分类委员会(ICTV)最近承认Endorna病毒是一个新属，它由水稻和蚕豆中大的(约14~17kbp)类似质粒的dsRNA复制组成。然而，内纳病毒的序列信息有限，只有4个dsRNAs被完全测序。从大麦、菜豆、甜瓜、葫芦、菠菜、海草和丝状螺旋藻中获得了依赖于RNA的RNA聚合酶的部分核苷酸序列。对这7个dsRNA与已知内源病毒和单链RNA病毒的系统发育分析表明，这些dsRNAs是内源病毒的新成员，广泛分布于植物和真菌中。这些dsRNA与其HO…之间的系统发育关系更多的植物表明dsRNA复制子的祖先是水平传递的。我们比较了携带dsRNA和不携带dsRNA的水稻培养细胞的总蛋白含量，发现了一些差异。这些结果表明，植物细胞中应该存在一种能够调节dsRNA复制子的宿主蛋白。我们推测宿主蛋白可以与dsRNA特异结合，该蛋白应该有一个保守的dsRNA结合基序(DsRBM)。我们对10种含拟南芥dsRBM的蛋白质进行了生化特征分析。HYL1/DRB1和三个HYL1同源物显示出显著的dsRNA结合活性。此外，我们还发现DRB4与DCL4特异地相互作用，而HYL1与DCL1的相互作用最强。这些结果表明，每一个HYL1/DRB家族蛋白都与四个Diller样蛋白中的一个特定的伙伴相互作用。这些数据表明，在体内，HYL1/DRB蛋白家族的每个成员都可能通过与类Diller蛋白的异源二聚体来单独调节Diller的功能。较少

We have found various double-stranded RNAs(dsRNAs) from many species of crops and wild plants. The International Committee on Taxonomy of Viruses(ICTV) recently accepted Endornavirus as a new genus, consisting of large (about 14 to 17 kbp) plasmid-like dsRNA replions in rice and broad bean. However, the sequence information of endornaviruses is limited and only four dsRNAs have been sequenced entirely. Partial nucleotide sequences of RNA-dependent RNA polymerase regions were obtained from large dsRNAs in barley (Hordeum vulgare), kidney bean (Phaseolus vulgaris), melon (Cucumis melo), bottle gourd (Lagenaria siceraria), Malabar spinach (Basella alba), seagrass (Zostera marina), and the fungus Helicobasidium mompa. Phylogenetic analyses of these seven dsRNAs with known endornaviruses and single-stranded RNA viruses indicate that these dsRNAs are new members of Endornavirus that are widely distributed over plants and fungi. The phylogenetic relationships between these dsRNAs and their ho … More st plants suggest that ancestors of dsRNA replicons were horizontally transmissible.We compared total protein contents between dsRNA-carrier and dsRNA-free rice cultured cells and detected some differences. These results suggest that a host protein, which can regulate the dsRNA replicons, should exist in a plant cell. We presumed that the host proteins could bind dsRNA specifically and this protein should have a conserved dsRNA-binding motif (dsRBM). We characterized biochemically ten Arabidopsis dsRBM-containing proteins. Two Dicer-like proteins (DCL1 and DCL3), HYL1/DRB1 and the three HYL1 homologs exhibit significant dsRNA-binding activity. Furthermore, we show that DRB4 interacts specifically with DCL4,and HYL1 most strongly interacts with DCL1. These results indicate that each HYL1/DRB family protein interacts with one specific partner among the four Dicer-like proteins. The presented data suggest that each member of the HYL1/DRB protein family may individually modulate Dicer function through heterodimerization with a Dicer-like protein in vivo. Less