| Muscle is an important part of the body and closely related to the economic characteristics of agricultural animals.Muscle fibers are divided into oxidative muscle fibers and glycolytic muscle fibers according to myoglobin content and metabolic enzyme activity.The ratio of oxidative muscle fibers is positively correlated with meat quality.Therefore,discovering the key genes that regulate skeletal muscle development and muscle fiber type transformation is of great significance to increase meat yield and improve meat quality.Long noncodingRNA(lncRNA)is a type of transcript with a length of more than200 nt,most of which have no coding potential and a small number ofRNAs that can encode small peptides.They are mostly involved in transcription,post-transcriptional,and chromatin conformation remodeling.Kind of biological process.However,the lncRNA that regulates the development of skeletal muscle and the conversion of muscle fiber types needs to be further explored.This study screened lncRNAs related to the conversion of muscle fiber types through the GEO(Gene expression omnibus)database,and found that the expression of lncRNA-COPS3 AS lncRNA in mouse extensor toe longus(glycolytic muscle fibers)was significantly higher than that of soleus muscle(oxidative muscle fiber),using bioinformatics analysis,EDU staining,flow cytometry,immunofluorescence staining and dual luciferase report analysis and other technical methods to explore the effects of COPS3 AS lncRNA on the proliferation and differentiation of myoblasts at the cellular level.The role and mechanism of muscle fiber type transformation.The main results obtained are as follows:1.Screening novel lncRNAs related to the conversion of muscle fiber types through the GEO database,it was found that the expression of a lncRNA in glycolytic muscle fibers was significantly higher than that in oxidative muscle fibers,and was expressed in the highest abundance in skeletal muscle,both nucleus and cytoplasm are distributed.there was210 bp with the COPS3 mRNA sense strand,thus,named it COPS3 AS lncRNA2.Knockdown of COPS3 AS lncRNA reduced the number of cells in S phase and Cyclin E and Cyclin D expression level,which are positively related to cell proliferation,promoted the expression of negatively related genes p21,and inhibited the proliferation of myoblasts.Knockdown of COPS3 AS lncRNA reduced the number of My HC-positive cells and cell differentiation index,down-regulated myocyte differentiation related gene My HC,Myo G and MyoD level,and finally inhibited myogenic differentiation.3.Knockdown of COPS3 AS lncRNA reduced the expression of glycolytic muscle fiber gene My HC-IIB and up-regulated the expression of oxidative muscle fiber gene My HC-I,resulted in the conversion of glycolytic muscle fiber into oxidative muscle fiber.In addition,konckdown of COPS3 AS lncRNA promoted mitochondrial biosynthesis by activating AMPK-PGC-1α signaling pathway.4.COPS3 AS lncRNA and COPS3 mRNA do not form AS lncRNA/mRNA dimers,which competitively bind to miR-762,promoted the expression of the target gene MyoD,caused the conversion of oxidative muscle fibers into glycolytic muscle fibers.In summary,this study screened a novel lncRNA named COPS3 AS lncRNA that regulates myogenic differentiation and muscle fiber type transformation,which acts as a miR-762 molecular sponge and weakens the inhibitory effect of miR-762 on the target gene MyoD.This study provides a theoretical basis for the regulation of lncRNA to increase pork production and improve meat quality. |
