Circular RNA (circRNA) is a kind of novel endogenous noncoding RNA formed through back-splicing of mRNA precursor. The biogenesis, degradation, nucleus–cytoplasm transport, location, and even translation of circRNA are controlled by RNA-binding proteins (RBPs). Therefore, circRNAs and the chaperoned RBPs play critical roles in biological functions that significantly contribute to normal animal development and disease. In this review, we systematically characterize the possible molecular mechanism of circRNA–protein interactions, summarize the latest research on circRNA–protein interactions in muscle development and myocardial disease, and discuss the future application of circRNA in treating muscle diseases. Finally, we provide several valid prediction methods and experimental verification approaches. Our review reveals the significance of circRNAs and their protein chaperones and provides a reference for further study in this field.

Muscle is one of the most critical organs for mammals, which governs multiple movement and physiological functions. Circular RNA (circRNA) is a kind of novel endogenous RNA without 5'-Caps and 3'-poly(A) structures formed by pre-mRNA's back-splicing. RNA binding proteins (RBPs) control the production and degradation of circRNA, help nucleus-cytoplasm transport and locate circRNA, and regulate circRNA translation. Therefore, circRNAs and the chaperoned RBPs play critical roles in muscle growth, development, and disease progression. In this review, we systematically characterize the possible molecular mechanism of circRNA-protein interactions. Also, we summarize the latest researches on circRNA-protein interactions in muscle development and diseases. Besides, we provide several valid prediction methods and experimental verification approaches. Our review reveals the importance of circRNAs and their protein chaperones and provides a reference for further study in this field.

Infrared thermography (IRT) imaging technology, as a convenient, efficient, and contactless temperature measurement technology, has been widely applied to animal production. In this review, we systematically summarized the principles and influencing parameters of IRT imaging technology. In addition, we also summed up recent advances of IRT imaging technology in monitoring the temperature of animal surfaces and core anatomical areas, diagnosing early disease and inflammation, monitoring animal stress levels, identifying estrus and ovulation, and diagnosing pregnancy and animal welfare. Finally, we made prospective forecast for future research directions, offering more theoretical references for related research in this field.

Insulin‐like growth factor 2 mRNA‐binding protein 1 (IGF2BP1) plays essential roles in the proliferation of skeletal muscle satellite cells (MuSCs). Increasing evidence has shown that IGF2BP1 regulates the expression of noncoding RNAs and mRNAs. However, the related molecular network remains to be fully understood. Therefore, we performed RNA sequencing and analyzed the microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and mRNAs differentially expressed in goat MuSCs treated with IGF2BP1 overexpressing and empty vectors. A total of 36 miRNAs, 59 lncRNAs, and 44 mRNAs were differentially expressed caused by IGF2BP1. Expectedly, they were enriched in muscle development‐related Rap1, PI3K‐AKT, and FoxO signaling pathways. Finally, we constructed a lncRNA‐miRNA‐mRNA interaction network containing 30 lncRNAs, 15 miRNAs, and 34 mRNAs, in which several miRNAs, including miR‐133a‐3p, miR‐204‐5p, miR‐125a‐3p, miR‐145‐3p, and miR‐423‐5p, relate with cell growth and participate in muscle development. Overall, we constructed an IGF2BP1‐related network, which provides new insight into the myogenic proliferation of goat.

AbstractmiRNAs are well known to be gene repressors. A newly identified class of miRNAs termed nuclear activating miRNAs (NamiRNAs), transcribed from miRNA loci that exhibit enhancer features, promote gene expression via binding to the promoter and enhancer marker regions of the target genes. Meanwhile, activated enhancers produce endogenous non-coding RNAs (named enhancer RNAs, eRNAs) to activate gene expression. During chromatin looping, transcribed eRNAs interact with NamiRNAs through enhancer-promoter interaction to perform similar functions. Here, we review the functional differences and similarities between eRNAs and NamiRNAs in myogenesis and disease. We also propose models demonstrating their mutual mechanism and function. We conclude that eRNAs are active molecules, transcriptional regulators, and partners of NamiRNAs, rather than mere RNAs produced during enhancer activation.

The proliferation and differentiation of mammalian skeletal muscle satellite cells (MuSCs) are highly complicated. Apart from the regulatory signaling cascade driven by the protein-coding genes, non-coding RNAs such as microRNAs (miRNA) and circular RNAs (circRNAs) play essential roles in this biological process. However, circRNA functions in MuSCs proliferation and differentiation remain largely to be elucidated. Here, we screened for an exonic circTCF4 based on our previous RNA-Seq data, specifically expressed during the development of the longest dorsal muscle in goats. Subsequently, the circular structure and whole sequence of circTCF4 were verified using Sanger sequencing. Besides, circTCF4 was spatiotemporally expressed in multiple tissues from goats but strikingly enriched in muscles. Furthermore, circTCF4 suppressed MuSCs proliferation and differentiation, independent of AGO2 binding. Finally, we conducted Poly(A) RNA-Seq using cells treated with small interfering RNA targeting circTCF4 and found that circTCF4 would affect multiple signaling pathways, including the insulin signaling pathway and AMPK signaling pathway related to muscle differentiation. Our results provide additional solid evidence for circRNA regulating skeletal muscle formation.

Background: Myogenesis is a complex process controlled by several coding and non-coding RNAs (ncRNAs) such as circular RNAs (circRNAs) that well-known function as endogenous microRNAs (miRNAs) sponges. Over the past few years, numerous circRNAs have been known and their roles in biological processes have begun to be understood. Cerebellar Degeneration-Related protein 1 antisense (CDR1as), the most spotlighted circRNA as miR-7 sponge that has been blooming circRNAs’ research for a decade, and can potentially sponge several miRNAs in disease and muscle physiology. Nevertheless, the linear-RNAs-differed character that the acute interventions for circRNAs do not affect miRNAs levels, and has retarded the transcriptome-wide discovery of miRNAs sponged by. Therefore, the purpose of this study was to provide the transcriptomic effect of CDR1as during muscle differentiation.Methods: siCDR1as and siDICER1 were transfected into goat skeletal muscle satellite cells (SMSCs). RNA-seq technology and bioinformatics tools were used to analyze genes that are deregulated by siCDR1as and siDICER1. quantitative PCR was used to verify the expression levels of the differentially expressed mRNAs and miRNAs. Results: Here, to systematically identify miRNAs targeting CDR1as, we employed the critical enzyme DICER1 that governs the biogenesis of miRNAs. The deficiency of either DICER1 or CDR1as inhibited myogenic differentiation of SMSCs, and knockdown of DICER1 decreased the expression of CDR1as. Moreover, we screened for the targeted messenger RNAs (mRNAs) and miRNAs in SMSCs transfected with siDICER1 or siCDR1as respectively and found out that some well-known muscle-related pathways such as phosphoinositide 3-kinase (PI3K)-AKT signaling pathway, Rap1 signaling pathway, and MAPK signaling pathway were enriched in all groups. Further, regarding the miRNAs identified in siDICER1 and siCDR1as together with the sequence complementary information, we identified 11 miRNAs including miR-1, miR-206, and miR-27a-5p which are more likely to be novel targets for CDR1as. Conclusion: In summary, our study provides a perspective on the potential functions and relationship between CDR1as and DICER1 during muscle development.

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