Mmu-Mir-21: Mmu-mir-21 is a microRNA that participates in cell differentiation by inhibiting genes related to pluripotency, such as Nanog, Sox2, and Pou5f1 [PMC9505168]. It is known as a differentiation-state-related miRNA and its highest expression is observed at E11.5 [PMC1421506]. Mmu-mir-21 has been studied in various contexts, including its role in gene regulation and its potential as a therapeutic target. In one study, the putative targets of mmu-mir-21 were aligned with upregulated genes to investigate its regulatory effects [PMC3907398]. In another study, the overexpression or inhibition of mmu-mir-21 was achieved using synthetic mimics or inhibitors [PMC4678163]. Mmu-mir-21 has also been implicated in the Lin28/let-7/Blimp1 pathway and PGC specification [PMC9563050]. Its expression levels have been quantified in serum samples of mice but no significant increases were observed [PMC5008393]. Additionally, mmu-mir-21 has been included in qPCR validation experiments along with other murine microRNAs to assess their expression levels [PMC3319598]. It has also been identified as one of the miRNAs upregulated after HFD-induced obesity and suggested as a potential research subject for future studies on obesity [PMC3319598]. Bioinformatic analysis revealed potential target hits for mmu-mir-21* and mmu-mir-21 that are not fully overlapped [PMC3329493].