A genetic link between epigenetic repressor AS1-AS2 and a putative small subunit processome in leaf polarity establishment of Arabidopsis.
A genetic link between epigenetic repressor AS1-AS2 and a putative small subunit processome in leaf polarity establishment of Arabidopsis.
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DOI：
10.1242/bio.019109
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发表时间：
2016-07-15
期刊：
影响因子：
2.4
通讯作者：
Machida Y
中科院分区：
文献类型：
--
作者：
Matsumura Y;Ohbayashi I;Takahashi H;Kojima S;Ishibashi N;Keta S;Nakagawa A;Hayashi R;Saéz-Vásquez J;Echeverria M;Sugiyama M;Nakamura K;Machida C;Machida Y
虽然DEAD-box RNA解旋酶家族在真核生物中普遍存在，但其发育作用尚不清楚。在这里，我们报道了拟南芥核仁蛋白RH10(人DEAD-box RNA解旋酶DDX47的同源基因)与不对称LEAVES1(AS1)和AS2(AS1-AS2)的表观遗传抑制复合体(AS1-AS2)之间的协同作用，这是抑制背面(腹面)基因ETT/ARF3和ARF4的关键，后者导致叶原基在茎尖近轴(背部)发育。RH10-1和AS2(或as1)的双重突变协同上调了远轴基因，从而产生了失去近轴结构域的离轴丝状叶片。DDX47是介导rRNA生物发生的小亚单位过程组(SSUP)的一部分。在RH10-1中，我们发现SSUP相关事件的各种缺陷，如：35S/33S rRNA前体积累；18S/25S比值降低；以及核仁肥大。AS2的双突变与编码其他SSUP相关成分的基因突变，如核仁素和可能的rRNA甲基转移酶，由于ETT/ARF3和ARF4的上调而显示出类似的协同缺陷。这些结果表明，SSUP和AS1-AS2之间可能存在紧密的联系，抑制决定细胞命运的远轴基因对近轴发育的决定。摘要：本文报道了核糖体RNA加工中核定位的表观遗传抑制因子和核仁定位的蛋白质之间的协同作用对拟南芥叶片极性建立的重要性。
Although the DEAD-box RNA helicase family is ubiquitous in eukaryotes, its developmental role remains unelucidated. Here, we report that cooperative action between the Arabidopsis nucleolar protein RH10, an ortholog of human DEAD-box RNA helicase DDX47, and the epigenetic repressor complex of ASYMMETRIC-LEAVES1 (AS1) and AS2 (AS1-AS2) is critical to repress abaxial (ventral) genes ETT/ARF3 and ARF4, which leads to adaxial (dorsal) development in leaf primordia at shoot apices. Double mutations of rh10-1 and as2 (or as1) synergistically up-regulated the abaxial genes, which generated abaxialized filamentous leaves with loss of the adaxial domain. DDX47 is part of the small subunit processome (SSUP) that mediates rRNA biogenesis. In rh10-1 we found various defects in SSUP-related events, such as: accumulation of 35S/33S rRNA precursors; reduction in the 18S/25S ratio; and nucleolar hypertrophy. Double mutants of as2 with mutations of genes that encode other candidate SSUP-related components such as nucleolin and putative rRNA methyltransferase exhibited similar synergistic defects caused by up-regulation of ETT/ARF3 and ARF4. These results suggest a tight link between putative SSUP and AS1-AS2 in repression of the abaxial-determining genes for cell fate decisions for adaxial development. Summary: This paper reports the importance of cooperative action between the nucleus-localized epigenetic repressor and the nucleolus-localized proteins involved in ribosomal RNA processing for polarity establishment of Arabidopsis leaves.