X. Q. Liu

Northwest A & F University, Yang-ling-chen, Shaanxi, China

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Publications (5)

  • X. Q. Liu · H. Y. Liu · Q. J. Chen · [...] · B. Y. Cao
    [Show abstract] [Hide abstract] ABSTRACT: Using animal mammary glands as bioreactors for producing commercially important proteins is a cutting-edge direction in the field of biotechnology development and application. Dairy goats are an important dairy livestock, with roughage-resistance, fast propagation, long lactation periods and high milk production per bodyweight; these characteristics make dairy goats ideal for use as mammary gland bioreactors. Foot-and-mouth disease virus 2A (FMDV 2A) is an efficient viral cleavage element that mediates proteolytic cleavage independent of the presence of other FMDV sequences. It is often incorporated into recombinant vectors to generate cleavage in the presence of heterologous sequences. To achieve specific co-expression of two heterologous genes in goat mammary gland epithelial (GMGE) cells, a mammary gland-specific bicistronic expression vector, pFIE beta, containing the beta-casein 5' flanking sequence and FMDV 2A, was successfully constructed and the specific expression of human interleukin 2 (hIL-2) and enhanced green fluorescent protein (EGFP) was conducted in primary GMGE cells. Another bicistronic expression vector, pFIEC, driven by the cytomegalovirus promoter, was constructed as a positive control. In cells transfected with pFIE beta and pFIEC, RT-PCR verified the existence of recombinant fusion mRNA of hIL-2 upstream of EGFP within the FMDV 2A cassette fragment and western blot analysis showed the existence of the fusion between hIL-2 and EGFP. It is concluded that FMDV 2A generated specific co-expression of multiple genes for the first time in primary GMGE cells driven by the beta-casein promoter.
    Article · Jan 2013 · Animal Production Science
  • [Show abstract] [Hide abstract] ABSTRACT: In this study, we reported the analysis of DGAT2 gene polymorphisms in 468 goats of two breeds: Xinong Saanen (SN) and Guanzhong (GZ). We identified three new allelic variants: P2 (C234A), P4 (C182T) and P5 (G301T) in SN and GZ breeds. Furthermore, P2 locus was a missense mutation (Leu>Met) in both breeds. Three genotypes were found at P2 (CC, CD and DD) and P4 (AA, AB and BB) loci in SN and GZ breeds, respectively. At P5 locus, EE and EF genotypes were found in both breeds. The SNP loci were in Hardy–Weinberg disequilibrium at P2 and P5 loci in SN and GZ breeds (P0.05). Association of polymorphisms with milk yield and fat percentage was done in both breeds, which showed that genotypes CC, CD (P2 locus) and EE (P5 locus) had higher milk yield and fat percentage. Some of those with better performance could be used for the breeding of improved genotypes of goat. Therefore, these results suggest that DGAT2 gene is a strong candidate gene that affects milk yield and fat percentage in goat.
    Article · Oct 2011 · Small Ruminant Research
  • X P An · J X Hou · G Li · [...] · B Y Cao
    [Show abstract] [Hide abstract] ABSTRACT: In this study, suppressive subtractive hybridization (SSH) was performed to screen differentially expressed genes in ovarian tissues between polytocous and monotocous goats. From the SSH cDNA library, we obtained 29 differentially expressed sequence tags (ESTs) that have high similarity with known genes in the public database, which were involved in signal transduction, transcriptional regulation, cellular molecular dynamics, cytoskeleton, metabolism and oxidation-reduction. In addition, one novel EST that has no similarity with known genes in the public database was obtained. Eight ESTs, TIMP1, NUCB1, OAZ1, CXXC5, CAPNS2, ATP5A1, Z and RPL5, were further examined for the reproducibility of the SSH data by the real-time quantitative PCR. The results confirmed an increased expression of respective mRNA in ovarian tissues of polytocous goats compared with those of monotocous goats. The study has identified several genes (known or unknown) that may have effect on follicular development, ovulation and egg activation in goats.
    Article · Sep 2011 · Reproduction in Domestic Animals
  • X.P. An · J.G. Wang · J.X. Hou · [...] · B.Y. Cao
    [Show abstract] [Hide abstract] ABSTRACT: The myostatin (MSTN) gene was studied as a candidate genetic marker for growth traits. We investigated polymorphisms of the MSTN gene in 664 individuals from four goat populations and applied PCR-SSCP and DNA sequencing analysis to reveal two single nucleotide polymorphisms (DQ167575: g.368A>C (p.Lys49Thr) and g.4911C>T. At g.368A>C locus, the frequencies of g.368A allele were 0.75-0.81, and the frequencies of g.368C allele were 0.19-0.25. At g.4911C>T locus, the frequencies of g.4911C allele were 0.76-0.82, and frequencies of g.4911T allele were 0.18-0.24. Compared to the female goats with AC genotype, those with AA genotype had superior body weight in Boer goats (15.69 ± 0.28 vs. 14.51 ± 0.31, P < 0.05) and F1 generation of Boer × Guanzhong dairy goats (19.39 ± 0.34 vs. 18.27 ± 0.33, P < 0.05). In addition, the female goats with AA genotype (45.80 ± 0.33 cm) had greater withers height than those with AC genotype (44.78 ± 0.36 cm) in F2 generation of Boer × Guanzhong dairy goats (P < 0.05). Hence, the biochemical and physiological functions along with the results obtained in our investigation suggest that the MSTN gene might play an important role in affecting the growth traits in goats.
    Article · Jan 2011 · Czech Journal of Animal Science
  • X.-Q. Liu · H. Dou · Y.-X. Song · [...] · Y.-Y. Hou
    Article · Jan 2011 · Chinese Pharmacological Bulletin