Instituto Gulbenkian de Ciência, Oeiras, Portugal.
J Exp Bot. 2011 Mar;62(5):1611-20. doi: 10.1093/jxb/erq452.
Most of the core proteins involved in the microRNA (miRNA) pathway in plants have been identified, and almost simultaneously hundreds of miRNA sequences processed in the Arabidopsis sporophyte have been discovered by exploiting next-generation sequencing technologies. However, there is very limited understanding about potentially distinct mechanisms of post-transcriptional regulation between different cell lineages. In this review the focus is on the Arabidopsis male gametophyte (pollen), where the germline differentiates after meiosis giving rise to the male gametes. Based on comparative analysis of miRNAs identified in sperm cells by in-depth sequencing, their possible functions during germ cell specification and beyond fertilization are discussed. In addition, 25 potentially novel miRNAs processed in sperm cells and pollen were identified, as well as enriched variations in the sequence length of known miRNAs, which might indicate subfunctionalization by association with a putative germline-specific Argonaute complex. ARGONAUTE 5 (AGO5), by close homology to AGO1 and localizing preferentially to the sperm cell cytoplasm in mature pollen, may be part of such a complex.
大多数参与植物 microRNA (miRNA) 途径的核心蛋白已经被鉴定出来，并且几乎同时，通过利用下一代测序技术，在拟南芥孢子体中处理了数百种 miRNA 序列。然而，对于不同细胞谱系之间潜在的不同转录后调控机制，我们的了解非常有限。在这篇综述中，重点关注拟南芥雄性配子体（花粉），其中生殖细胞在减数分裂后分化为雄性配子。基于通过深度测序鉴定的精子细胞中的 miRNA 的比较分析，讨论了它们在生殖细胞特化和受精后的可能功能。此外，鉴定出了 25 种可能在精子细胞和花粉中加工的新 miRNA，以及已知 miRNA 序列长度的富集变化，这可能表明通过与假定的生殖特异性 Argonaute 复合物的关联而亚功能化。ARGONAUTE 5 (AGO5)，与 AGO1 密切同源，并在成熟花粉的精子细胞质中优先定位，可能是这种复合物的一部分。
