荣昌猪和长荣猪肌肉生长抑制素基因表达规律的研究

为了研究荣昌猪和长荣猪胴体瘦肉率和骨骼肌肌肉生长抑制素( MSTN)基因表达量的变化规律,试验采用2×2因子试验设计,荣昌猪和长荣猪(两种基因型猪)分别饲喂按中国瘦肉型猪饲养标准和荣昌猪饲养标准配制的日粮,共4个处理,每个处理6个重复,在20 kg、35 kg、50 kg、80 kg和110 kg时每个重复屠宰1头.结...     

猪肌肉生长抑制素基因的研究进展

肌肉生长抑制素(MSTN)是骨骼肌生长发育的负调控因子。其活性的丧失或降低，会引起动物肌肉的过度发育，表现为双肌征状。最早在小鼠中发现该基因，随后通过荧光原位杂交法将猪MSTN基因定位于15q2.3上，进而分析了MSTN以及其分子结构，比较。MSTN基因在不同物种间的同源性。     

品种和体重对猪肌肉生长抑制素表达的影响

本文旨在研究猪的体重和品种对其背最长肌的肌肉生长抑制素基因表达的影响,并对猪100kg时的胴体性状与肌肉肌肉生长抑制素基因表达量的相关性进行分析。试验采用荧光定量PCR方法,以β-actin基因为内标,研究不同体重(20、50和100kg)和品种(汉普夏猪和长白×撒坝猪)对猪背最长肌的肌肉生长抑制素基因表达的影响,同时考察试验猪在100kg时的胴体肉质指标。结果表明:①猪背最长肌中肌肉生长抑制素的表达随体重的增加呈上升的趋势(P>0.05);②相同体重条件下长撒猪背最长肌中肌肉生长抑制素表达均显著高于汉普夏猪(P<0.05),其中20kg时达到极显著水平(P<0.01);③肌肉生长抑制素的表达与瘦肉率呈极显著的负相关(P<0.01),与背膘厚则呈极显著的正相关(P<0.01),与滴水损失和肌内脂肪的相关性不显著(P>0.05)。本研究结果表明猪背最长肌的肌肉生长抑制素基因的表达量随体重增加而提高,品种间差异显著,并且肌肉生长抑制素基因的表达与瘦肉率、背膘厚存在显著的相关性。     

肌肉生长抑制素研究进展

肌肉生长抑制素是一种分泌型的多肽。小鼠中该基因的缺失可导致骨骼肌的明显增大,而且在双肌牛中该基因的缺失产生了突变,这表明肌肉生长抑制素可能是骨骼肌生长的负调控因子。本文综述了肌肉生长抑制素的基因结构及其分子作用机制,并就它对动物体成分的影响、应用及尚存在的问题作了概述。     

猪肌肉生长抑制素基因启动子的克隆与鉴定

利用PCR方法从猪基因组DNA中扩增了1.2 kb的肌肉生长抑制素(myostatin)基因启动子序列。并进一步以绿色荧光蛋白(GFP)为报告基因,构建了真核表达载体MSTNPro-EGFP;通过转染C2C12小鼠骨骼肌成肌细胞和猪成纤维细胞,对猪myostatin基因启动子的转录调控活性进行鉴定。结果表明:猪myostatin基因启动子可以启动GFP在C2C12细胞中的转录和表达,而将猪MSTNPro-EGFP载体转染猪胎儿成纤维细胞后并未观察到GFP的表达,说明myostatin基因表达的肌肉特异性源于启动子的转录特异性。     

肌肉生长抑制素调控肌肉和脂肪组织代谢的研究进展

肌肉生长抑制素(myostatin,MSTN),又名生长分化因子-8(growth differentiation factor 8,GDF-8),是一种主要由骨骼肌分泌的蛋白质,在肌肉生长发育过程中起负调控作用。若MSTN基因编码区碱基突变或缺失,可以导致肌肉异常肥大,出现典型的"双肌"性状。近年来研究还发现,MSTN在脂肪组织中也表达,并在脂肪沉积的过程中发挥重要调控作用。因此,本文将从MSTN的基因结构、组织分布、作用机制以及功能等几个方面的相关研究进展进行综述,重点阐述其在肌肉和脂肪组织中的调控作用及机制,以期更深入了解MSTN,为畜牧业新品种的改良和肉质性状的改善奠定理论基础。     

肌肉生长抑制素的研究进展

肌肉生长抑制素(简称肌抑素)属TGF-β超家族,是骨骼肌生长的负调控因子,参与肌纤维增生和肥大的调控。本文综述了肌肉生长抑制素蛋白的结构、活性调控、信号转导途径以及肌抑素基因的表达和生物学作用。     

肌肉生长抑制素对动物肌肉、脂肪和骨骼的影响

肌肉生长抑制素是转化生长因子 β超家族成员之一,具有众多的生理功能。近来的研究表明,肌肉生长抑制素除对肌肉生长有负调控作用外,还对脂肪的沉积和骨骼的生长发育具有调节作用,甚至还能影响肌腱和韧带的强硬度。本文主要从肌肉生长抑制素的结构、基因表达及其对动物肌肉、脂肪和骨骼的作用等方面进行综述。     

肌肉生长抑制素(MSTN)的研究进展

通过回顾前人的研究,综述了肌肉生长抑制素(MSTN)的发现、基础研究,以及近年来在人类和畜禽业中的研究进展,并探讨了MSTN基因的应用前景。     

猪肌肉生长抑制素基因的克隆及原核表达

本试验旨在通过基因工程方法获得重组肌肉生长抑制素蛋白。根据基因库肌肉生长抑制素基因序列设计合成特异性引物,引物两端分别加上EcoRⅠ和SalⅠ酶切位点及保护碱基,提取汉普夏猪的骨骼肌总RNA,用RT-PCR方法扩增肌肉生长抑制素全长基因,并将其克隆到pMD18-T载体上,测序后EcoRⅠ和SalⅠ双酶切,克隆到pET-30a( )中,构建原核表达载体pET-30a-M,将重组表达质粒转化至E.coliBL21(DE3)中,诱导表达。结果表明,成功扩增出肌肉生长抑制素全长基因;克隆载体经过DNA序列测定,所得基因与国外报道的完全一致;成功构建原核表达载体pET-30a-M;经IPTG诱导,表达出了6×His-M融合蛋白,用组氨酸标签抗体做Western印记证明产物大约48 ku,与预期大小相符,肌肉生长抑制素蛋白在大肠杆菌中成功的进行了表达。     

不同品种猪抑肌素基因启动区的RFLP分析

瘦肉率是猪育种中重要的目标性状之一 ,其大小与骨骼肌的量密切相关。猪抑肌素基因是与瘦肉率有关的基因之一 ,本研究以大白、长白、杜洛克、民猪、三江白猪和军牧Ⅰ号为研究对象 ,采用限制性酶切片段生长度多态性 (RFLP)分子标记法对抑肌素基因的启动区进行了酶切多态性分析。结果表明 :大白、长白、杜洛克以等位基因T为主 :三江白猪和军牧Ⅰ号全部是TT型 ;民猪 3种基因型均有且频率近乎相等     

Effects of active immunization against myostatin on carcass quality and expression of the myostatin gene in pigs

The study was conducted to investigate the effects of active immunization against myostatin on the titer of myostatin antibody, carcass evaluation, activity of creatine kinase and the expression of the myostatin gene in pigs. Eighteen pigs were allotted into three groups (six pigs per group), and pigs in treatment 1, 2 and 3 were immunized with physiological saline, 1 mg or 4 mg myostatin per pig, respectively. Six pigs were killed by electrical stunning followed by exsanguination at BW of 100 kg. The results indicated that the titer of myostatin antibody was increased in treated groups compared to the control group on day 42 ( P  < 0.01) and d 84 ( P  < 0.01). The carcass lean percentage was significantly increased in the treatment groups compared to the control group ( P  < 0.01), and intramuscular fat was significantly decreased in the 4 mg group compared to the control group ( P  < 0.05). The muscle creatine kinase activity of pigs treated with 1 mg and 4 mg myostatin was lower than the control group. The immunization of myostatin signofocantly decreased the myostatin gene expression levels in muscle. It was concluded that optimal active immunization against myostatin could increase the content of myostatin antibody, suppress the activity of creatine kinase and the expression of myostatin gene, and therefore improve the carcass lean percentage for pigs.     

牛肌肉生成抑制素基因功能区的克隆与原核表达

根据GenBank中牛肌肉生成抑制素（MSTN）基因序列设计了1对引物，在引物两端分别加EcoRⅠ和XhoⅠ识别位点。利用RT—PCR技术扩增出了牛MSTN功能区序列。分别构建克隆和原核表达载体，酶切、PCR鉴定及测序分析表明，该基因功能区序列的克隆载体和原核表达载体已成功构建。筛选阳性菌，经IPTG诱导，牛MSTN基因功能区在大肠埃希氏菌中成功表达。     

The Blonde d’Aquitaine T3811>G3811 mutation in the myostatin gene: association with growth,carcass, and muscle phenotypes in veal calves

The mutation T3811 → G3811 (TG3811) discovered in the myostatin gene of the Blonde d’Aquitaine breed is suspected of contributing to the outstanding muscularity of this breed. An experiment was designed to estimate the effect of this mutation in an F2 and back-cross Blonde d’Aquitaine × Holstein population. By genotyping all known mutations in the myostatin gene, it was ensured that the TG3811 mutation was indeed the only known mutation segregating in this population. Fifty-six calves (43 F2, 13 back-cross) were intensively fattened and slaughtered at 24.0 ± 1.4 wk of age. The effects of the mutation were estimated by comparing the calves with the [T/T] (n = 18), [T/G] (n = 30), and [G/G] (n = 8) genotypes. Highly significant substitution effects (P < 0.001), above + 1.2 phenotypic SD, were shown on carcass yield and muscularity scores. Birth weight (P < 0.001) was positively affected by the mutation (+0.8 SD) but not growth rate (P = 0.97), while carcass length (P = 0.03), and fatness (P ≤ 0.03) were negatively affected (–0.5 to –0.7 SD). The characteristics of the Triceps brachii muscle were affected by the mutation (P < 0.001), with lower ICDH activity (oxidative) and a higher proportion of myosin type 2X muscle fibers (fast twitch). The effects of the TG3811 mutation were similar to those of other known myostatin mutations, although the Blonde d’Aquitaine animals, which are predominantly [G/G] homozygous, do not exhibit extreme double muscling.     

猪肌生成抑制素C末端80氨基酸编码基因的合成及其原核表达

将猪肌生成抑制素编码序列下游883～1 126 bp按大肠杆菌嗜好密码子进行优化,将优化后序列双链分成12个单链片段(F1、F2、F3、R6、R5、R4、F4、F5、F6、R3、R2、R1),采用化学合成方法合成,每对相邻互补片段之间有20 bp序列交叉重叠.F1长38 bp,R1长36 bp,其他片段均40bp长,F1和R1片段两端分别加上限制性内切酶Nco I和Xho I的识别位点序列.经PCR扩增出254 bp片段,该片段与pMD18-T载体连接,转化JM109感受态细胞,所得阳性克隆进行测序分析,得到的克隆序列与设计的序列完全一致,表明成功地获得了猪肌生成抑制素下游编码序列克隆载体.从阳性细菌中提取质粒,经Nc0 I和Xho I酶切,回收254 bp目的片段,定向克隆到pET28a中,转化DH5.受体菌,提取质粒,再转化到BL21(DE3)中,成功筛选出阳性克隆.阳性菌经IPTG诱导,通过SDS PAGE,检测出猪肌生成抑制素的表达.     

牛肌肉生成抑制素基因真核表达载体的构建及其在COS-7细胞中的表达

将构建的牛pMD 18-T-MSTN克隆载体与真核表达载体pef-dhfr1a酶切,回收牛MSTN目的片段及pef-dhfr1a载体,构建了牛MSTN基因的真核表达质粒pef-dhfr1a-MSTN,然后转染COS-7细胞,将牛MSTN成熟蛋白编码序列在COS-7细胞中进行了表达.提取转染细胞的总RNA,采用RT-PCR和Western-blotting方法,分别从mRNA水平和蛋白质水平上检测到了牛MSTN基因在COS-7细胞中的表达产物,证明已经成功构建出该基因的真核表达载体.     

Differential expression of myostatin and its receptor in the porcine anterior pituitary gland

Myostatin (MSTN), known as growth and differentiation factor 8 (GDF-8), is a member of the transforming growth factor β (TGF-β) superfamily that negatively regulates skeletal muscle mass. Myostatin binds with high affinity to the receptor serine threonine kinase activin receptor type IIB (ActRIIB). Activins that also belong to the TGF-β superfamily, stimulate follicle-stimulating hormone production in gonadotrophs and suppress growth hormone and adrenocorticotropic hormone production in somatotrophs and corticotrophs, respectively. The aim of the present paper was therefore to clarify the endocrine action of MSTN in adenohypophysis. The present study details the expression and cellular localization of MSTN and ActRIIB in porcine anterior pituitary gland. The mRNA of MSTN and ActRIIB was consistently expressed in RT-PCR. Immunohistochemistry of MSTN and specific hormones showed that MSTN localized in thyrotrophs and gonadotrophs, in which most of the MSTN immunoreactive cells were identified as thyrotrophs. The immunostaining of ActRIIB was restricted to corticotrophs. These results indicate that MSTN was mainly produced in thyrotrophs and its receptor, ActRIIB, was restrictively contained in corticotrophs. Interestingly, thyrotrophs immunoreactive for MSTN were frequently close to corticotrophs immunoreactive for ActRIIB. The present study suggests that MSTN from thyrotrophs may regulate corticotroph function as a paracrine mediator among the porcine anterior pituitary cells.     

互助猪胴体性状和肉脂品质的测定及其相关分析

测定了２５头互助猪的胴体性能和肉脂品质，结果表明，互助猪的胴体性能远远劣于国外瘦肉型猪，但优于国内某些地方猪种，瘦肉率低是其显著特点；肉脂品质优于国外瘦肉型猪，表现在良好肉色和肌间脂肪含量，相关分析表明，互助猪的产瘦肉能力与肉脂品质呈出一定的拮抗关系，表现为胴体瘦肉率愈高，背膘愈薄，肌间脂肪含量就愈低，贮存损失率也愈大。     

猪胴体在线瘦肉率回归预测研究

选购不同类型的商品猪94头,分别测其瘦肉率、胴体重、背膘厚度等指标,并以瘦肉率为因变量,其它指标为自变量,采用SAS8.0软件进行数据分析,建立了不同商品猪胴体瘦肉率最优回归方程,并对回归方程进行了方差分析及残差散点图的回归诊断,结果表明只采用胴体重和背膘厚度两个指标所得的胴体瘦肉率预测方程具有较高的准确度和精度度。     

Ob基因对松辽黑猪肉质和胴体性状的影响

以松辽黑猪为研究对象,分析Ob基因对其肉质和胴体性状的影响。测定30头松辽黑猪的9个肉质性状和6个胴体性状,用PCR-RFLP方法检测Ob基因型。结果显示,松辽黑猪TT基因型平均膘厚比CT基因型低,而肌内脂肪含量、瘦肉率则显著高于后者(P<0.05),其他肉质和胴体性状在Ob基因型间没有显著差异(P>0.05)。结果表明,Ob基因的TT基因型对猪的肉质和胴体性状具有显著的正遗传效应。