Characterization of a Read-through Fusion Transcript, BCL2L2-PABPN1, Involved in Porcine Adipogenesis

Effects of HOXC8 on the Proliferation and Differentiation of Porcine Preadipocytes

Transcription factor Homeobox C8 (HOXC8) is identified as a white adipose gene as revealed by expression profile analysis in fat tissues. However, the specific role of HOXC8 in fat accumulation remains to be identified. This study was designed to reveal the effects of HOXC8 on preadipocyte proliferation and differentiation. We first make clear that the expression of HOXC8 is associated with fat contents in muscles, highlighting a role of HOXC8 in fat accumulation. Next, it is demonstrated that HOXC8 promotes the proliferation and differentiation of preadipocytes through gain- and loss-of-function assays in primary cultured porcine preadipocytes. Then, mechanisms underlying the regulation of HOXC8 on preadipocyte proliferation and differentiation are identified with RNA sequencing, and a number of differentially expressed genes (DEGs) in response to HOXC8 knockdown are identified. The top GO (Gene Ontology) terms enriched by DEGs involved in proliferation and differentiation, respectively, are identical. IL-17 signaling pathway is the common one significantly enriched by DEGs involved in preadipocyte proliferation and differentiation, respectively, indicating its importance in mediating fat accumulation regulated by HOXC8. Additionally, we find that the inhibition of proliferation is one of the main processes during preadipocyte differentiation. The results will contribue to further revealing the mechanisms underlying fat accumulation regulated by HOXC8.

Genome-wide association analysis of milk production, somatic cell score, and body conformation traits in Holstein cows

Milk production and body conformation traits are critical economic traits for dairy cows. To understand the basic genetic structure for those traits, a genome wide association study was performed on milk yield, milk fat yield, milk fat percentage, milk protein yield, milk protein percentage, somatic cell score, body form composite index, daily capacity composite index, feed, and leg conformation traits, based on the Illumina Bovine HD100k BeadChip. A total of 57, 12 and 26 SNPs were found to be related to the milk production, somatic cell score and body conformation traits in the Holstein cattle. Genes with pleiotropic effect were also found in this study. Seven significant SNPs were associated with multi-traits and were located on the PLEC, PLEKHA5, TONSL, PTGER4, and LCORL genes. In addition, some important candidate genes, like GPAT3, CEBPB, AGO2, SLC37A1, and FNDC3B, were found to participate in fat metabolism or mammary gland development. These results can be used as candidate genes for milk production, somatic cell score, and body conformation traits of Holstein cows, and are helpful for further gene function analysis to improve milk production and quality.

Genome-wide characterization of lncRNAs and mRNAs in muscles with differential intramuscular fat contents

Meat quality is one of the most important traits in pig production. Long non-coding RNAs (lncRNAs) have been involved in diverse biological processes such as muscle development through regulating gene expression. However, studies on lncRNAs lag behind and a comparatively small number of lncRNAs have been identified in pigs. Also, the effects of lncRNAs on meat quality remain to be characterized. Here, we analyzed lncRNAs in longissimus thoracis (LT) and semitendinosus (ST) muscles, being different in meat quality, with RNA-sequencing technology. A total of 500 differentially expressed lncRNAs (DELs) and 2,094 protein-coding genes (DEGs) were identified. Through KEGG analysis on DELs, we first made clear that fat deposition might be the main reason resulting in the differential phenotype of LT and ST, for which cGMP–PKG and VEGF signaling pathways were the most important ones. In total, forty-one key DELs and 50 DEGs involved in the differential fat deposition were then characterized. One of the key genes, cAMP-response element binding protein 1, was selected to confirm its role in porcine adipogenesis with molecular biology methods and found that it promotes the differentiation of porcine preadipocytes, consistent with its higher expression level and intramuscular fat contents in LT than that in ST muscle. Furthermore, through integrated analysis of DELs and DEGs, transcription factors important for differential fat deposition were characterized among which BCL6 has the most target DEGs while MEF2A was targeted by the most DELs. The results provide candidate genes crucial for meat quality, which will contribute to improving meat quality with molecular-breeding strategies.