microRNA（miRNA）途徑參與許多生物學過程,。本文中,，研究人員在線蟲中對于miRNA途徑中兩個特異蛋白進行了研究，試圖發(fā)現(xiàn)miRNA在調(diào)節(jié)生物學事件中更多的功能,。
ALG-1和ALG2是Argonaute蛋白家族的成員,，研究人員發(fā)現(xiàn)，突變的ALG-1和ALG-2會導致線蟲的子代數(shù)量減少,。進一步分析顯示,，在ALG-1和ALG-2突變的個體中，有絲分裂的生殖細胞減少,，并且有一部分細胞會提前進入減數(shù)分裂階段,。在野生型線蟲中，ALG-1特異表達在頂端細胞（distal tip cell,，DTC),。在頂端細胞內(nèi)表達有功能的ALG-1可以一定程度上修復突變體中生殖細胞的缺陷。有趣的是,，阻礙5個miRNA的表達也會導致類似的表型,。
研究人員表示，這一結(jié)果說明,，microRNA途徑調(diào)節(jié)線蟲生殖細胞的增殖和分化中起著重要的作用,，同時該研究也揭示了miRNA的一項新功能。（生物谷 Bioon.com ）
doi:10.1038/cr.2012.31
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The microRNA pathway controls germ cell proliferation and differentiation in C. elegans
Syed Irfan Ahmad Bukhari, Alejandro Vasquez-Rifo, Dominic Gagné, Eric R Paquet, Monique Zetka, Claude Robert, Jean-Yves Masson and Martin J Simard
The discovery of the miRNA pathway revealed a new layer of molecular control of biological processes. To uncover new functions of this gene regulatory pathway, we undertook the characterization of the two miRNA-specific Argonaute proteins in Caenorhabditis elegans, ALG-1 and ALG-2. We first observed that the loss-of-function of alg-1 and alg-2 genes resulted in reduced progeny number. An extensive analysis of the germline of these mutants revealed a reduced mitotic region, indicating fewer proliferating germ cells. We also observed an early entry into meiosis in alg-1 and alg-2 mutant animals. We detected ALG-1 and ALG-2 protein expressions in the distal tip cell (DTC), a specialized cell located at the tip of both C. elegans gonadal arms that regulates mitosis-meiosis transition. Re-establishing the expression of alg-1 specifically in the DTC of mutant animals partially rescued the observed germline defects. Further analyses also support the implication of the miRNA pathway in gametogenesis. Interestingly, we observed that disruption of five miRNAs expressed in the DTC led to similar phenotypes. Finally, gene expression analysis of alg-1 mutant gonads suggests that the miRNA pathway is involved in the regulation of different pathways important for germline proliferation and differentiation. Collectively, our data indicate that the miRNA pathway plays a crucial role in the control of germ cell biogenesis in C. elegans.
