The ribonuclease Dicer is a multidomain enzyme that plays a fundamental role in the biogenesis of small regulatory RNAs (srRNAs), which control gene expression by targeting complementary transcripts and inducing their cleavage or repressing their translation. Recent studies of Dicer's domains have permitted to propose their roles in srRNA biogenesis. For all of Dicer's domains except one, called DUF283 (domain of unknown function), their involvement in RNA substrate recognition, binding or cleavage has been postulated. For DUF283, the interaction with Dicer's protein partners has been the only function suggested thus far. In this report, we demonstrate that the isolated DUF283 domain from human Dicer is capable of binding single-stranded nucleic acids in vitro. We also show that DUF283 can act as a nucleic acid annealer that accelerates base-pairing between complementary RNA/DNA molecules in vitro. We further demonstrate an annealing activity of full length human Dicer. The overall results suggest that Dicer, presumably through its DUF283 domain, might facilitate hybridization between short RNAs and their targets. The presented findings reveal the complex nature of Dicer, whose functions may extend beyond the biogenesis of srRNAs.

中文翻译：

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揭示了人类Dicer DUF283域的新活性。

核糖核酸酶切酶酶是一种多结构域酶，在小调节RNA（srRNA）的生物合成中起基本作用，小调节RNA通过靶向互补转录本并诱导其切割或抑制其翻译来控制基因表达。Dicer域的最新研究已允许提出其在srRNA生物发生中的作用。对于除一个称为DUF283（功能未知的域）以外的所有Dicer域，都假定它们参与RNA底物识别，结合或切割。对于DUF283，到目前为止，与Dicer的蛋白质伴侣的相互作用一直是唯一建议的功能。在此报告中，我们证明了从人切丁机分离的DUF283结构域能够在体外结合单链核酸。我们还显示，DUF283可以充当核酸退火仪，在体外加速互补RNA / DNA分子之间的碱基配对。我们进一步证明了全长人切丁机的退火活性。总体结果表明，Dicer大概通过其DUF283结构域，可能有助于短RNA与它们的靶标之间的杂交。提出的发现揭示了Dicer的复杂性质，其功能可能超出srRNA的生物合成。