The THO complex is required for nucleolar integrity in Drosophila spermatocytes
The THO complex is required for nucleolar integrity in Drosophila spermatocytes
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DOI：
10.1242/dev.056945
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发表时间：
2011-09-01
期刊：
影响因子：
4.6
通讯作者：
Chung, Yun Doo
中科院分区：
文献类型：
--
作者：
Moon, Sungjin;Cho, Bongki;Chung, Yun Doo
THO复合物是一种保守的多亚基蛋白复合物，在形成可输出的信使核糖核蛋白（mRNP）中发挥作用。虽然复合物已在单细胞水平上进行了广泛的研究，但其在多细胞生物体水平上的确切作用却知之甚少。在这里，我们分离到一个新的果蝇雄性不育突变体，garmcho（garm）。定位克隆表明，Garm编码果蝇THO复合物的一个亚基，THOC 5。缺乏THOC 5的果蝇表现出减数分裂停滞表型，初级精母细胞中出现严重的核仁破坏。一个功能性的GFP标记的融合蛋白，THOC 5-GFP，揭示了一个独特的模式THOC 5定位在核仁附近。睾丸特异性TATA结合蛋白（TBP）相关因子（tTAF）的核仁分布，SA，这是需要负责精子分化的基因的表达，被严重破坏突变体睾丸缺乏THOC 5。但是，无论是tTAF靶mRNA还是tTAF非依赖性mRNA的表达和核输出，THOC 5似乎在很大程度上是不稳定的。两者合计，我们的研究表明，果蝇THO复合物是必要的适当的精子发生的贡献建立或维持核仁的完整性，而不是在精母细胞核mRNA的出口。
The THO complex is a conserved multisubunit protein complex that functions in the formation of export-competent messenger ribonucleoprotein (mRNP). Although the complex has been studied extensively at the single-cell level, its exact role at the multicellular organism level has been poorly understood. Here, we isolated a novel Drosophila male sterile mutant, garmcho (garm). Positional cloning indicated that garm encodes a subunit of the Drosophila THO complex, THOC5. Flies lacking THOC5 showed a meiotic arrest phenotype with severe nucleolar disruption in primary spermatocytes. A functional GFP-tagged fusion protein, THOC5-GFP, revealed a unique pattern of THOC5 localization near the nucleolus. The nucleolar distribution of a testis-specific TATA binding protein (TBP)-associated factor (tTAF), SA, which is required for the expression of genes responsible for sperm differentiation, was severely disrupted in mutant testes lacking THOC5. But THOC5 appeared to be largely dispensable for the expression and nuclear export of either tTAF target mRNAs or tTAF-independent mRNAs. Taken together, our study suggests that the Drosophila THO complex is necessary for proper spermatogenesis by contribution to the establishment or maintenance of nucleolar integrity rather than by nuclear mRNA export in spermatocytes.