The selection of suitable reference genes is crucial to accurately evaluate and normalize the relative expression level of target genes for gene function analysis. However, commonly used reference genes have variable expression levels in developing skeletal muscle. There are few reports that systematically evaluate the expression stability of reference genes across prenatal and postnatal developing skeletal muscle in mammals. Here, we used quantitative PCR to examine the expression levels of 15 candidate reference genes ( ACTB , GAPDH , RNF7 , RHOA , RPS18 , RPL32 , PPIA , H3F3 , API5 , B2M , AP1S1 , DRAP1 , TBP , WSB , and VAPB ) in porcine skeletal muscle at 26 different developmental stages (15 prenatal and 11 postnatal periods). We evaluated gene expression stability using the computer algorithms geNorm, NormFinder, and BestKeeper. Our results indicated that GAPDH and ACTB had the greatest variability among the candidate genes across prenatal and postnatal stages of skeletal muscle development. RPS18 , API5 , and VAPB had stable expression levels in prenatal stages, whereas API5 , RPS18 , RPL32 , and H3F3 had stable expression levels in postnatal stages. API5 and H3F3 expression levels had the greatest stability in all tested prenatal and postnatal stages, and were the most appropriate reference genes for gene expression normalization in developing skeletal muscle. Our data provide valuable information for gene expression analysis during different stages of skeletal muscle development in mammals. This information can provide a valuable guide for the analysis of human diseases.
Sirtuin 5 (SIRT5) is a NAD - dependent lysine deacylase. To investigate the potential role of SIRT5 and acylation in obesity and Type 2 Diabetes (T2D), we established and characterized the hepatic SIRT5 - overexpressing ob/ob mice (ob/ob - SIRT5 OE). The ob/ob - SIRT5 OE mice showed decreased malonylation and succinylation, improved cellular glycolysis, suppressed glyconeogenesis, enhanced fatty acid oxidation, and attenuated hepatic steatosis. A total of 955 malonylation sites on 434 proteins and 1,377 succinylation sites on 429 proteins were identified and quantitated. Further analysis revealed that malonylation was the major SIRT5 target in the glycolysis/gluconeogenesis pathway, while succinylation was the preferred SIRT5 target in the oxidative phosphorylation pathway. Our data suggested that hepatic overexpression of SIRT5 ameliorated the metabolic abnormalities of ob/ob mice, probably through demalonylating and desuccinylating proteins in the main met abolic pathways.Declaration of Interests: The authors declare no competing interests.Funding: This work was supported by the National Natural Science Foundation of China (31671175, 31771257, 61773025), the Strategic Priority Research Programs (Category A) of the Chinese Academy of Sciences (XDA12030207), the National Key R&D Program of China (2017YFA0205501), the interdisciplinary medicine Seed Fund of Peking University (BMU2017MB001) and the National Laboratory of Biomacromolecules.The study design was approved by the appropriate ethics review boards.
Abstract The differentiation of myoblasts plays a key role in the growth of biological individuals and the reconstruction of muscle tissue. Several microRNAs are significantly upregulated during the differentiation of myoblasts and their target genes have been explored. However, the molecular mechanisms underlying the transcriptional regulation of microRNAs remain elusive. In the present study, we found that the expression of miR-133a is increased during the differentiation of C2C12 myoblasts. miR-133a mimic is sufficient to induce the biogenesis of mitochondria and differentiation of C2C12 myoblasts whereas miR-133a inhibitor abolishes cell differentiation. Using CRISPR affinity purification in situ of regulatory elements (CAPTURE) technique, we further dissected the regulatory mechanisms of miR-133a expression and found that KAP1-associated transcription complex accounts for the suppression of miR-133a in C2C12 myoblasts. Knockdown of KAP1 increased the expression of miR-133a, which contributed to the biogenesis of mitochondria and differentiation of C2C12 myoblasts. To our knowledge, this is the first study using the CAPTURE technology to identify the regulatory factors of miR-133a during cell differentiation, which may provide new ideas for understanding the precision regulatory machinery of microRNAs during different biological processes.
Abstract Despite modest sequence conservation and rapid evolution, long non-coding RNAs (lncRNAs) appear to be conserved in expression pattern and function. However, analysis of lncRNAs across tissues and developmental stages remains largely uncharacterized in mammals. Here, we systematically investigated the lncRNAs of the Guizhou miniature pig ( Sus scrofa ), which was widely used as biomedical model. We performed RNA sequencing across 9 organs and 3 developmental skeletal muscle, and developed a filtering pipeline to identify 10,813 lncRNAs (9,075 novel). Conservation patterns analysis revealed that 57% of pig lncRNAs showed homology to humans and mice based on genome alignment. 5,455 lncRNAs exhibited typical hallmarks of regulatory molecules, such as high spatio-temporal specificity. Notably, conserved lncRNAs exhibited higher tissue specificity than pig-specific lncRNAs and were significantly enriched in testis and ovary. Weighted co-expression network analysis revealed a set of conserved lncRNAs that are likely involved in postnatal muscle development. Based on the high degree of similarity in the structure, organization, and dynamic expression of pig lncRNAs compared with human and mouse lncRNAs, we propose that these lncRNAs play an important role in organ physiology and development in mammals. Our results provide a resource for studying animal evolution, morphological complexity, breeding, and biomedical research.
BackgroundSirtuin 5 (SIRT5) is a NAD+-dependent lysine deacylase. The SIRT5 deficiency mouse model shows that it is dispensable for metabolic homeostasis under normal conditions. However, the biological role of SIRT5 and acylation in pathological states such as obesity and type 2 diabetes (T2D) remains elusive.MethodsThe hepatic SIRT5-overexpressing ob/ob mouse model (ob/ob-SIRT5 OE) was established by CRISPR/Cas9 gene editing tool Protein malonylation and succinylation lysine sites were identified by immunoprecipitation coupled lipid chromatography - tandem mass spectrometry (LC-MS/MS) methods.FindingsThe ob/ob-SIRT5 OE mice showed decreased malonylation and succinylation, improved cellular glycolysis, suppressed gluconeogenesis, enhanced fatty acid oxidation, and attenuated hepatic steatosis. A total of 955 malonylation sites on 434 proteins and 1377 succinylation sites on 429 proteins were identified and quantitated. Bioinformatics analysis revealed that malonylation was the major SIRT5 target in the glycolysis/gluconeogenesis pathway, whereas succinylation was the preferred SIRT5 target in the oxidative phosphorylation pathway.InterpretationHepatic overexpression of SIRT5 ameliorated the metabolic abnormalities of ob/ob mice, probably through demalonylating and desuccinylating proteins in the main metabolic pathways. SIRT5 and related acylation might be potential targets for metabolic disorders.FundNational Key R&D Program of China, the National Natural Science Foundation of China, the Strategic Priority Research Programs (Category A) of the Chinese Academy of Sciences, the Interdisciplinary Medicine Seed Fund of Peking University and the National Laboratory of Biomacromolecules.
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