Analysis Of Histological Characteristics And MRNA And LncRNA Regulatory Network Of Goat Longissimus Dorsal Muscle In Seven Stages From Fetuses To Kids

Muscle development is regulated by a series of complex and precise processes.mRNAs and lncRNAs play essential roles in the regulation of skeletal muscle formation.In this study,paraffin section was used to explore the histological changes of goat's longissimus dorsal muscle at seven stage from fetal to postnatal,including fetal at 45?F45?,65?F65?,90?F90?,120?F120?,and 135?F135?days,and kids at 1?B1 day and 90?B90?day.And RNA-seq was used to analyze the temporal module of differentially expression mRNAs and IncRNAs,and screen for important lncRNAs.1?The paraffin section observed that the number of muscle cells was not large at F45,but amount of connective tissue could be observed.A large number of muscle cells have appeared between connective tissues at F65.The F65 and F90 stages had primary muscle fibers,while in F120,F135,B1 and B90 stages,the primary muscle fibers were disappeared and completely converted to secondary muscle fibers.2)All libraries identified 4,793 and 547 differentially expressed mRNAs and lncRNAs,respectively.The differentially expressed mRNAs and lncRNAs indicated that F1 20 was the transitional stage of F90 and F135.Six randomly selected mRNAs and lncRNAs were identified by qPCR.And the expression trends of all transcripts were consistent with RNA-seq.3)The differential expressed mRNAs were divided into 4 modules.M-turquoise was enriched in functions and pathways for cell proliferation and cytoskeleton formation.M-grey was involved in skeletal muscle energy supply and growth,and might be involved in intramuscular fat formation.M-brown was involved metabolism and biosynthesis processes in skeletal muscle.M-blue was related to ATP energy supply of skeletal muscle.4)The differentially expressed lncRNA was classified into three types,including early module,late modules,and specific stage modules.The early module was L-blue,which involved in muscle fiber structure and energy metabolism.Late modules were L-brown and L-yellow.L-brown was involved in substance binding and complex regulation in muscle fibers.L-yellow was involved in the regulation of muscle protein and cytoskeleton.Specific stage modules were L-turquoise and L-grey.L-turquoise was associated with protein transfer to the nucleus to activate of cells,myogenesis and metabolism.L-grey was not enriched.Finally,we selected LNC₀11371,LNC₀07561,and LNC₀01728 as the key lncRNAs of the three type modules.These results elucidated the functional transformation of mRNAs and lncRNAs at different stages of longissimus dorsal muscle development and enriched the regulatory network for skeletal muscle formation and development.