The RNA-binding protein LIN28A is required for maintaining tissue homeostasis, including in the reproductive system, but the underlying mechanisms on how LIN28A regulates germline progenitors remain unclear. Here, we dissected LIN28A-binding targets using high-throughput sequencing of RNAs isolated by crosslinking immunoprecipitation (HITS-CLIP) in the mouse testes. LIN28A preferentially binds to mRNA coding sequence (CDS) or 3'UTR regions at sites enriched with GGAG(A) sequences. Further investigation of Lin28a-null mouse testes indicated that meiosis-associated mRNAs bound by LIN28A were differentially expressed. Next, ribosome profiling revealed that the mRNA levels of these targets were significantly reduced in the polysome fractions, and their protein expression levels decreased, in Lin28a-null mouse testes, even when meiotic arrest in the null mouse testes was not apparent. Collectively, these findings provide a set of LIN28A-regulated target mRNAs, and show that LIN28A binding might be a mechanism through which LIN28A acts to regulate undifferentiated spermatogonia fates and male fertility in mammals.

RNA 结合蛋白 LIN28A 是维持组织稳态（包括生殖系统）所必需的，但 LIN28A 如何调节种系祖细胞的潜在机制仍不清楚。在这里，我们使用交联免疫沉淀 (HITS-CLIP) 在小鼠睾丸中分离的 RNA 的高通量测序来剖析 LIN28A 结合靶标。LIN28A 优先结合 mRNA 编码序列 (CDS) 或富含 GGAG(A) 序列的位点的 3'UTR 区域。对Lin28a缺失小鼠睾丸的进一步研究表明，LIN28A 结合的减数分裂相关 mRNA 存在差异表达。接下来，核糖体分析显示，在Lin28a缺失小鼠睾丸中，这些靶标的 mRNA 水平在多核糖体级分中显着降低，并且它们的蛋白质表达水平降低，即使在缺失小鼠睾丸中减数分裂停滞不明显时也是如此。总的来说，这些发现提供了一组 LIN28A 调节的靶 mRNA，并表明 LIN28A 结合可能是 LIN28A 调节哺乳动物未分化精原细胞命运和雄性生育力的机制。