bmo-mir-2758: Bmo-mir-2758 is a silkworm-specific miRNA that exhibits high sequence reads, comparable to abundant conserved miRNAs [PMC2838851]. Its expression in the posterior silk gland (PSG) increases gradually during larval development, reaching the highest levels on day 5 of the fifth instar [PMC4801057]. The bmo-mir-2758 inhibitor (anti-sense RNA) has been shown to restrain the posttranscriptional regulation function of bmo-mir-2758 [PMC4801057]. Bmo-mir-2758 significantly downregulates the expression of BmFMBP-1 at a posttranslational level by binding to its 3’-UTR complementary site [PMC4801057]. The primary sequence of bmo-mir-2758, pri-bmo-mir-2758, has been cloned into an expression vector to construct a bmo-mir-2758 expression plasmid [PMC4801057]. The relative expression levels of both bmo-mir-2758 and BmFMBP-1 in different silk gland regions at different developmental stages have been analyzed via semi-quantitative RT-PCR [PMC4801057]. In vitro experiments have shown that bmo-mir-2758 significantly inhibits the expression of BmFMBP-1 (P < .01) [PMC4801057]. The relative expression of bmo-mir-2758 is higher in PSG compared to mid-silk gland (MSG), suggesting that it mainly regulates BmFMBP1 in PSG [PMC4801057]. Co-transfection experiments have confirmed successful transfection and effective expression of bmo-miR 2758 in BmN cells using recombinant plasmids [PMC4801057]. Further studies are needed to understand the regulation of bmo-mir-2758 on the expression of BmFMBP-1 and other silk gland transcription factors in vivo [PMC4801057]. This study provides the first discussion on the expression of bmo-mir-2758 in fifth-instar silkworm larvae [PMC4801057].