The Analysis Of Lpl, C/ebpα Genes’ Expression In Tail Adipose Tissues Of Sheep With Different Types Of Tail

This study was conducted to explore the relationship between the expression level ofLPL, C/EBPα and fat deposition of sheep tails. This disertation provides basic information forfurther exploring the mechanism of blocking excessive deposition of tail fat, and makes fulluse of the excellent productivity of the sheep population.Primers were designed based on the full length of bovine （Bos taurus） C/EBPα gene（GenBank No. NM₁76784.2）. RT-PCR was used to amplify the C/EBPα gene, andbioinformatics methods were used to analyze the characteristics of genetic sequence andprotein. Quantitative real-time PCR and Western blot were used to evaluate the expressionlevel of C/EBPα and LPL in tail adipose tissues among five sheep （Ovis aries） breeds（Shannbei Merino （long thin-tail）, Tong Sheep （long/short fat-tail）, Tibetan Sheep （shortthin-tail）, Tan Sheep （long fat-tail） and Kazak Sheep （hip fat-tail）） aged9-month-old. A totalof18individuals were involoved. Tail adipose tissues from six developmental stages （3,6,9,12,15and18-month-old） were collected from18healthy rams （3for each month with similarweight）. The expression patterns of LPL and C/EBPα mRNA in tail adipose tissues weremeasured. Moreover, by comparison of the LPL and C/EBPα expression level in tail adiposetissue, subcutaneous adipose tissue and longissimus dorsi of Tan Sheep （long fat-tail） andShaanbei Merino （short thin-tail） which stand for two breeds with different types of tails.20-day-old sheep tail fat was used as the test sample, and isolated preadipocytes by enzymaticdigestion, studied the regulation of preadipocytes’ proliferation and differentiation, andevaluated the mRNA expression level of LPL and C/EBPα during the differentiation process（0,2,4,6,8and10d）. The main research results were as follows:1. The full-length of sheep C/EBPα gene sequence was successfully cloned,bioinformatics methods showed that the coding region of C/EBPα was1062bp in length,encoding353amino acids, the molecular weight of the protein was37150.8Da, sharing99%similar nucleotides with bovine sequences and its protein contained a typical leucine zipperdomain.2. The expression trends between the protein and mRNA in LPL and C/EBPα were roughly the same. Both C/EBPα and LPL were highly expressed in fat-tailed （Tong Sheep,Tan Sheep） and hip fat-tailed （Kazak Sheep） sheep, while lower expression levels inthin-tailed （Shannbei Merino, Tibetan Sheep） breeds. In the same breed, the mRNA and theprotein expression levels of C/EBPα and LPL in adipose tissues of long fat-tail in Tong Sheepwere significantly higher than those short fat-tail （P<0.05）. The expression levels of C/EBPαand LPL genes showed significant correlations with fat deposition in tail tissues of sheep.3. The expression levels of LPL and C/EBPα mRNA had developmental changes in tailadipose tissues of Tan Sheep, both LPL and C/EBPα had higher expression levels at3,9,18-month-old Tan Sheep, and shared significant differences in comparison with the othermonths （P<0.05）, suggesting a down-up-down-up tendency through all the developmentalstages selected.4. Compared of the Shannbei Merino, both of the two genes had higher expression levelsin tail adipose tissues of Tan Sheep, although C/EBPα had higher expression levels insubcutaneous adipose tissue of Shannbei Merino. Showing that excessive deposition of fat intail had greater effects on the distribution of body fat, and these two genes may have differentpatterns in adipose deposition from sheep breeds with different tail-type.5. The primary preadipocytes from sheep tails were successfully cultured, and inducedprimary preadipocytes to differentiate into mature adipocytes. The mRNA expression levelsof LPL and C/EBPα during different phases of differentiation was evaluated. The resultsproved that the expression LPL was earlier than C/EBPα during the differentiation ofpreadipocytes.