CircRNAs are newly identified special endogenous RNA molecules that covalently close a loop by back-splicing with pre-mRNA. In the cytoplasm, circRNAs would act as molecular sponges to bind with specific miRNA to promote the expression of target genes. However, knowledge of circRNA functional alternation in skeletal myogenesis is still in its infancy. In this study, we identified a circRNA–miRNA–mRNA interaction network in which the axis may be implicated in the progression of chicken primary myoblasts’ (CPMs) myogenesis by multi-omics (i.e., circRNA-seq and ribo-seq). In total, 314 circRNA–miRNA–mRNA regulatory axes containing 66 circRNAs, 70 miRNAs, and 24 mRNAs that may be relevant to myogenesis were collected. With these, the circPLXNA2-gga-miR-12207-5P-MDM4 axis aroused our research interest. The circPLXNA2 is highly differentially expressed during differentiation versus proliferation. It was demonstrated that circPLXNA2 inhibited the process of apoptosis while at the same time stimulating cell proliferation. Furthermore, we demonstrated that circPLXNA2 could inhibit the repression of gga-miR-12207-5p to MDM4 by directing binding to gga-miR-12207-5p, thereby restoring MDM4 expression. In conclusion, circPLXNA2 could function as a competing endogenous RNA (ceRNA) to recover the function of MDM4 by directing binding to gga-miR-12207-5p, thereby regulating the myogenesis.

Background: circRNAs are new-identified special endogenous RNA molecules that covalently close a loop by backsplicing with pre-mRNA. In the cytoplasm, circRNAs would act as molecular sponges to bind with specific miRNA to promote the expression of target genes. However, there is still in its fancy of knowing circRNA functional alternation in skeletal myogenesis. In this study, we favor a model to identify the circRNA-miRNA-mRNA interaction network in which the axis may be implicated in the progression of chicken primary myoblasts (CPMs) myogenesis by a combination of multi-omics (i.e., circRNA-seq and ribo-seq). Results: In total, 314 circRNA-miRNA-mRNA regulatory axis containing 66 circRNAs, 70 miRNAs, and 24 mRNAs that may be relevant to myogenesis were collected. With these, the circPLXNA2-gga-miR-12207-5P-MDM4 axis aroused our research interest. The circPLXNA2 is highly differentially expressed during differentiation versus proliferation. It was demonstrated that circPLXNA2 inhibited the process of apoptosis while at the same time stimulating cell proliferation. Furthermore, we demonstrated that circPLXNA2 could inhibit the repression of gga-miR-12207-5p to MDM4 by directing binding to gga-miR-12207-5p, thereby restoring MDM4 expression. Conclusions: CircPLXNA2 could function as a competing endogenous RNA (ceRNA) to inhibit the repression of gga-miR-12207-5p to MDM4 by directing binding to gga-miR-12207-5p, thereby recovering the expression of MDM4.

In order to reveal the effect of disturbance on species composition and detect indicator species for disturbance gradients, we conducted an investigation of urban forest communities along a disturbance gradient in Guangzhou, China. Species richness in the tree layer and understory had no significant difference among disturbance gradients, but Simpson index, Shannon-Weiner index and Evenness index varied significantly.species diversity index decreased with disturbance gradient. Multi-Response Permutation Procedures (MRPP) revealed high significance in species composition of both tree and understory layer among different disturbance gradients. Twelve species from the tree layer and 25 from the understory were detected to characterize the forest communities with a certain disturbance regime by Indicator Species Analysis (ISA). Indicator species help enhance our understanding of species-environment relationship, and the ecological response of indicator species to disturbance can be used for monitoring forest environmental change.