RNA结合蛋白Musashi1（MSI1）在多种癌症中显示出增加的表达水平，并已被引入为某些恶性肿瘤的预后标志物。预期如果该基因编码某些miRNA，则其可能在癌症发展中发挥作用或可被视为预后生物标志物。因此，在本研究中，我们旨在发现MSI1基因内部错位区域中的新的miRNA（s）。在这里，我们报道了两个在MSI1基因的第四个错位区域内的新的miRNA，命名为MSM2和MSM3，这些miRNA是在生物信息学研究中预测的多个miRNA前体中选出的。实验分析中，相应的前体miRNA被转染到HEK293T细胞中，并检测到了成熟miRNA的外源表达。其中两个成熟miRNA，即MSM3-3p和MSM3-5p是由MSM3前体生成的，而MSM2-5p是来自于MSM2。此外，MCF-7和SH-SY5Y细胞系中检测到了MSM2-5p和MSM3-3p的内源表达。这两个成熟miRNA的表达也在乳腺癌的临床样本中检测到。此外，通过双荧光素酶报告试验，证实了MSM3-3p与PDE11A的3'UTR区域之间的相互作用。总的来说，我们的数据证明了在乳腺癌细胞中MSI1基因编码了两个新的miRNA。© 2023. Springer Nature Limited.

RNA-binding protein Musashi1 (MSI1) shows an increased expression level in several cancers and has been introduced as a prognostic marker in some malignancies. It is expected that if any miRNA is encoded by this gene, it might have a role in cancer development or could be considered as a prognostic biomarker. Accordingly, in this study, we aimed to find novel miRNA(s) inside the intronic regions of the MSI1 gene. Here, we report two novel miRNAs within intron 4 of MSI1 gene, named MSM2 and MSM3, which were selected among several miRNA precursors predicted by bioinformatic studies. For experimental analysis, corresponding precursor miRNAs were transfected into HEK293T cells and exogenous expression of the mature miRNAs were detected. Two mature miRNAs, MSM3-3p and MSM3-5p were generated by MSM3 precursor and one, MSM2-5p was derived from MSM2. Besides, endogenous expression of MSM2-5p and MSM3-3p was detected in MCF-7 and SH-SY5Y cell lines. Expression of both mature miRNAs was also detected in clinical samples of breast cancer. Additionally, the interaction between the MSM3-3p and 3'UTR region of PDE11A was confirmed by dual luciferase assay. Overall, our data demonstrated that MSI1 gene encodes two novel miRNAs in breast cancer cells.© 2023. Springer Nature Limited.