Howard Hughes Medical Institute, Department of Biology, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Curr Biol. 2010 Feb 23;20(4):367-73. doi: 10.1016/j.cub.2009.12.051. Epub 2010 Jan 21.
MicroRNAs (miRNAs) are approximately 23 nt regulatory RNAs that posttranscriptionally inhibit the functions of protein-coding mRNAs. We previously found that most C. elegans miRNAs are individually not essential for development or viability and proposed that paralogous miRNAs might often function redundantly. To test this hypothesis, we generated mutant C. elegans strains that each lack multiple or all members of one of 15 miRNA families. Mutants for 12 of these families did not display strong synthetic abnormalities, suggesting that these miRNA families have subtle roles during development. By contrast, mutants deleted for all members of the mir-35 or mir-51 families died as embryos or early larvae, and mutants deleted for four members of the mir-58 family showed defects in locomotion, body size, and egg laying and an inability to form dauer larvae. Our findings indicate that the regulatory functions of most individual miRNAs and most individual families of miRNAs related in sequence are not critical for development or viability. Conversely, because in some cases miRNA family members act redundantly, our findings emphasize the importance of determining miRNA function in the absence of miRNAs related in sequence.
微小 RNA（miRNAs）是大约 23 个核苷酸的调控 RNA，可在后转录水平抑制蛋白编码 mRNA 的功能。我们之前发现，大多数秀丽隐杆线虫 miRNAs 个体对于发育或生存并非必需，并提出了同源 miRNAs 可能经常冗余地发挥作用。为了验证这一假说，我们生成了缺失一个 miRNA 家族中多个或全部成员的秀丽隐杆线虫突变株。这 15 个 miRNA 家族中的 12 个家族的突变体并未表现出强烈的合成异常，表明这些 miRNA 家族在发育过程中具有细微的作用。相比之下，mir-35 或 mir-51 家族所有成员缺失的突变体在胚胎或早期幼虫期死亡，mir-58 家族四个成员缺失的突变体在运动、体型、产卵和不能形成 dauer 幼虫方面存在缺陷。我们的研究结果表明，大多数个体 miRNAs 和在序列上相关的 miRNAs 家族的调节功能对于发育或生存并非关键。相反，由于在某些情况下 miRNA 家族成员具有冗余作用，因此我们的研究结果强调了在缺乏相关序列 miRNA 的情况下确定 miRNA 功能的重要性。
