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ABSTRACT. Beef cattle breeding programs focus on improving important economic traits, including growth rates, and meat quantity and quality. Molecular marker-assisted selection based on genetic variation represents a potential method for breeding genetically improved livestock with better economic traits. Smoothened (SMO) protein is a signal transducer that contributes to the regulation of both osteogenesis and adipogenesis through the hedgehog pathway. In this study, we detected polymorphisms in the bovine SMO gene of Qinchuan cattle, and we analyzed their associations with body measurement traits (BMTs) and meat quality traits (MQTs). Using DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism, 3 novel single nucleotide polymorphisms were identified in the SMO gene of 562 cattle: 1 G > C mutation on exon 9 (G21234C) and 2 C > T mutations on exon 11 (C22424T and C22481T). Association analysis showed that polymorphisms on both the G21234C and C22424T loci significantly affected certain BMTs and MQTs (P < 0.05 or P < 0.01), whereas those on the C22481T locus did not (P > 0.05). Therefore, the SMO gene could be used as a candidate gene to alter BMTs and MQTs in Qinchuan cattle or for marker-assisted selection to breed cattle with superior BMTs and MQTs.

Fatty acid binding protein 4 (FABP4) is a member of the FABP family of proteins that bind fatty acids and play important roles in fatty acid uptake and intracellular transport. In the present study, we cloned the 5'-regulatory region of bovine and identified its transcription initiation sites. Sequence comparative analysis demonstrated amino acids and promoter sequences of were highly conservative in mammals. Real-time PCR analysis revealed the products of bovine were very highly expressed in subcutaneous adipose tissue. Serial deletion constructs of the bovine 5'-regulatory region evaluated in a dual-luciferase reporter assay showed that 209 bp upstream from the transcription initiation site was its core promoter. An electrophoretic mobility shift assay combined with a site-directed mutation experiment indicated that peroxisome proliferator activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein β (C/EBPβ), and sterol regulatory element-binding protein (SREBP) were important transcription factors for bovine . These results provide an important basis for further understanding the regulation of bovine .

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ABSTRACT. The peroxisome proliferator-activated receptor gamma (PPAR-γ) is a key molecule in adipocyte differentitation; it transactivates multiple target genes in lipid metabolic pathways. Using PCR-SSCP and DNA sequencing, we evaluated a potential association of an SNP (72472 G﹥T in exon7) of the bovine PPAR-γ gene with carcass and meat quality traits in 660 individuals from five Chinese indigenous cattle breeds, Qinchuan (QC), Luxi (LX), Nanyang (NY), Jiaxian (JX), and Xianan (XN). This 72472 G﹥T mutation identified a missense mutation, Q448H. Two alleles were named C and D. Allele frequencies of PPAR-γ-C/D in the five breeds were 0.78/0.22, 0.90/0.10, 0.74/0.26, 0.71/0.29, and 0.83/0.17 for QC, NY, JX, LX, and XN, respectively. Except for the XN breed, all breeds were in Hardy-Weinberg equilibrium at this locus. The polymorphism information content was low for NY and XN (0.16 and 0.24, respectively), while it was moderately high for QC, JX, and LX (0.28, 0.31 and 0.33, respectively). Correlation analysis showed significant association of this missense mutation with carcass length, backfat thickness and water holding capacity in the QC breed. Animals with the genotype CD had significantly greater carcass length than those with genotypes CC and DD, while animals with genotype CC had significantly greater backfat thickness than those with genotypes CD and DD. Animals with genotype CC had lower water holding capacity than those with the genotypes CD and DD. In conclusion, this locus is a candidate for a major quantitative trait locus affecting production traits and could be used for beef breeding selection.

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CCAAT/enhancer binding protein delta (C/EBPδ), an important transcriptional factor, regulates cell growth, differentiation and adipogenesis in humans and mice. However, we lack of directive information on the effects of C/EBPδ gene in bovine cells. In the present study, we cloned the CDS areas of bovine C/EBPδ gene and predicted its sequence characteristics. Moreover, we constructed the recombinant adenovirus plasmids of bovine C/EBPδ gene and harvested the subsequent adenoviruses to infect bovine primary fibroblasts. Oil Red O staining results showed lipid droplets accumulated gradually in the adenoviruses treated fibroblasts. Time course real-time PCR results indicated that over-expression of exogenous C/EBPδ regulated the mRNA expression levels of some key adipogenic genes, herein, activated the C/EBPα expression, increased lipoprotein lipase and fatty acid binding protein 4 mRNA expression levels, whereas inhibited leptin receptor gene. In conclusion, the present study demonstrates that the elevated C/EBPδ can induce the adipogenesis in the fibroblasts of cattle.