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Muscle development is regulated under a series of complicate processes, and non-coding RNAs, such as microRNAs (miRNAs) and circular RNAs (circRNAs), have been reported to play important roles in regulating myoblast proliferation and differentiation. We found that miR-107 expression was high in skeletal muscle of Qinchuan cattle. Overexpression of miR-107 inhibited bovine myoblasts differentiation and protected cells from apoptosis. Wnt3a was identified as a target of miR-107 by luciferase activity, real-time qPCR, and western blotting assays. Knockdown of Wnt3a inhibited bovine myoblasts differentiation and apoptosis, and this effect was similar to miR-107 overexpression. We also found circFGFR4 to promote myoblasts differentiation and to induce cell apoptosis. Via luciferase screening and RNA pull-down assays, circFGFR4 was observed to sponge miR-107. Overexpression of circFGFR4 increased the expression of Wnt3a, whereas this effect was abolished by miR-107. These results demonstrated that circFGFR4 binding miR-107 promotes cell differentiation via targeting Wnt3a in bovine primary myoblasts.

The average length of genes in a eukaryote is larger than in a prokaryote, implying that evolution of complexity is related to change of gene lengths. Here, we show that although the average lengths of genes in prokaryotes and eukaryotes are much different, the average lengths of genes are highly conserved within either of the two kingdoms. This suggests that natural selection has clearly set a strong limitation on gene elongation within the kingdom. Furthermore, the average gene size adds another distinct characteristic for the discrimination between the two kingdoms of organisms.

Sclerotinia sclerotiorum causes a highly destructive disease in oilseed rape (Brassica napus). Oxalic acid (OA) secreted by the pathogen is a key pathogenicity factor. Oxalate oxidase (OXO) can oxidize OA into CO2 and H2O2. In this study, we show that transgenic oilseed rape (sixth generation lines) constitutively expressing wheat (Triticum aestivum) OXO displays considerably increased OXO activity and enhanced resistance to S. sclerotiorum (with up to 90.2 and 88.4% disease reductions compared with the untransformed parent line and a resistant control, respectively). Upon application of exogenous OA, the pH values in transgenic plants were maintained at levels slightly lower than 5.58 measured prior to OA treatment, whereas the pH values in untransformed plants decreased rapidly and were markedly lower than 5.63 measured prior to OA treatment. Following pathogen inoculation, H2O2 levels were higher in transgenic plants than in untransformed plants. These results indicate that the enhanced resistance of the OXO transgenic oilseed rape to Sclerotinia is probably mediated by OA detoxification. We believe that enhancing the OA metabolism of oilseed rape in this way will be an effective strategy for improving resistance to S. sclerotiorum.

BackgroundMicroRNAs (miRNAs) are a family of ~22 nucleotide small RNA molecules that regulate gene expression by fully or partially binding to their complementary sequences. Recently, a large number of miRNAs and their expression patterns have been identified in various species. However, to date no miRNAs have been reported to modulate muscle development in beef cattle.ResultsTotal RNAs from the Chinese Qinchuan bovine longissimus thoracis at fetal and adult stages were used to construct small RNA libraries for Solexa SBS technology sequencing. A total of 15,454,182 clean reads were obtained from the fetal bovine library and 13,558,164 clean reads from the adult bovine library. In total, 521 miRNAs including 104 novel miRNA candidates were identified. Furthermore, the nucleotide bias, base edit and family of the known miRNAs were also analyzed. Based on stem-loop qPCR, 25 high-read miRNAs were detected, and the results showed that bta-miRNA-206, miRNA-1, miRNA-133, miRNAn12, and miRNAn17 were highly expressed in muscle-related tissue or organs, suggesting that these miRNAs may play a role in the development of bovine muscle tissues.ConclusionsThis study confirmed the authenticity of 417 known miRNAs, discovered 104 novel miRNAs in bos taurus, and identified five muscle-specific miRNAs. The identification of novel miRNAs significantly expanded the repertoire of bovine miRNAs and could contribute to further studies on the muscle development of cattle.