进行性肌营养不良患者Myo

进行性肌营养不良是一组以进行性骨骼肌萎缩和无力为特征的肌源性肌病.肌肉抑制素(Myostatin)是最近发现的骨骼肌生长发育抑制因子.为探讨Myostatin基因与进行性肌营养不良病理发生的相关性,采用RT-PCR方法克隆了患者的Myostatin基因并测序、分析肌营养不良患者是否存在Myostatin基因突变;然后采用半定量RT-PCR方法检测患者中Myostatin基因的表达水平是否发生改变,同时用Western blot方法分析了肌营养不良患者中Myostatin蛋白的表达情况.结果发现,所研究的肌营养不良患者中没有携带Myostatin基因突变,但一些患者的Myostatin基因转录水平降低,部分患者Myostatin蛋白加工障碍.结果提示,一些类型(亚型)的进行性肌营养不良可能与肌肉抑制素Myostatin基因表达异常、蛋白加工障碍有关.     

Duchenne肌营养不良基因缺陷及基因治疗

Duchenne肌营养不良(DMD)是常见的神经肌肉遗传病之一,由于骨胳肌肌膜上的抗肌萎缩蛋白(dys—trophin)完全或部分缺失引起。本文介绍了dystrophin的结构和功能,对DMD基因治疗的目的基因。基因治疗方式(包括病毒载体和非病毒载体)。基因转染途径作了较为全面的介绍,指出腺相关病毒载体介导的基因治疗及干细胞移植是有希望的治疗方向。经全身途径使目的基因广泛转染骨胳肌并实现心肌和膈肌的转染,是基因治疗研究的难点。     

两个DMD cDNA片段在进行性肌营养不良症基因诊断中的应用

本文使用了缺失热点区的两个DMD cDNA片段1b-2a及8为探针检测Duc-henne型及Becker型肌营养不良(DMD/BMD)患者的基因缺失。在34例不相关患者中分别检测到5例及8例基因片段缺失,缺失检测率分别为14.7％及23.5％,总检出率为38.2％。结果表明,中国肌营养不良患者的基因缺失也不是随机分布的,主要集中于基因中心附近,其次在基因5′侧。     

猪肌生成抑制素基因成熟蛋白编码序列的表达与纯化

猪肌生成抑制素(myostatin,MSTN)基因的cDNA去除信号肽后PCR扩增出成熟蛋白编码序列1．2kb片段,将该片段与pMD18-T载体连接。转化JM109受体菌细胞;筛选阳性克隆测序分析,结果表明与设计序列完全一致。将该克隆载体的质粒DNA用带有BamHI和Sall内切酶识别序列的另一对引物进行PCR扩增,将回收的1.2 kb PCR目的片段定向克隆到pET28a( )表达载体上。成功地构建了编码绪肌生成抑制素成熟蛋白的原核表达载体。LB液体培养基中用IPTG诱导表达,SDS—PAGE显示重组菌表达的MSTN蛋白以包涵体形式存在;经薄层扫描仪扫描分析SDS-PAGE凝胶,表达的MSTN包涵体蛋白占菌体不溶性蛋白含量的27．9％,其相对分子质量为41451．3。所构建的表达载体中含六聚组氨酸标签,HisTrap亲和柱纯化后纯度可达92．5％。该试验为获得较好的绪肌生成抑制素并制备抗体打下了良好的基础。     

鸡Myostatin基因单核苷酸多态性的群体遗传学分析

肌肉生长抑制素是控制骨骼肌生长发育的重要细胞因子,采用PCR－SSCP和测序的方法发现了5个位于Myostatin基因5′－和3′－调控区的单核苷酸多态性位点,对北京油鸡、白耳鸡、石歧杂、矮小黄鸡、小型黄鸡、惠阳胡须鸡、隐性白羽鸡、海兰、AA鸡等不同鸡种的该单核苷酸多态性分析结果表明：Myostatin基因的5′调控区引物P60／P61扩增片段多态性是由3个核苷酸的改变而产生的[分别是G→A（304位）、A→G（322位）、G→（344位）],引物P93／P94扩增片段的多态性是由G→A（167位）突变造成的,引物P117。P118PC扩增片段多态性是由T→C（177位）造成的。3′调控我引物P80／P81扩增片段多态性是由第7263位A突变为T造成的,引物P76／P77扩增片段多态性是由A→G（6935位）造成的。不同鸡种群体遗传学分析表明,5′－调控区引物60／P61扩增片段多态性片段多态性是由A→G（6935位）造成的。不同鸡种群体遗传学分析表明,5′－调控区引物P60／P61扩增片段多态性位点在北京油鸡的基因型频率分布与其他的品种有很大的差异,其BB型频率为0．700,AA基因型频率仅为0．033,而其他鸡种中以A基因优势;对于引物P93／P94,品种间的基因型频率差异极显著（P＜0．01）,北京油鸡和AA鸡的EE型频率鸡种中以A基因占优势;对于引物P93／P94,品种间的基因型频率差异极显著（P＜0．01）,北京油鸡和AA鸡的EE型频率低于其他品种,白耳鸡和海兰蛋鸡以EE型为主,其频率高于其他品种;3′－调控区引物P80／P81多态怀位点在9个鸡种中都是等位基因C占优势。引物P76／P77,总体上MM型的频率较低,杂合子MN型的频率较高。     

Duchenne肌营养不良的基因治疗进展

Ｄｕｃｈｅｎｎｅ肌营养不良（ＤＭＤ）基因治疗的目的是补充骨骼肌和心肌内已经缺失的抗肌萎缩蛋白，本文对ＤＭＤ基因治疗中目的基因的选择，基因靶向，载体的选择，目的基因的运送途径等方面作一综述。     

迷你基因与肌营养不良症治疗

一项有关小鼠的研究显示，用一种缩短的“迷你”基因所进行的基因疗法可能是治疗肌营养不良症的一种新的方法。     

东北地区抗肌营养不良蛋白基因缺失的研究及应用

为了解东北地区Duchenne／Becker型肌营养不良症患者基因缺失的分布及进行产前基因诊断,用12对引物以多重PCR法检测120例DMD／BMD患者,并分析缺失型患者dystrophin基因的断裂点分布及各引物优化组合,并将高危男性胎儿行缺失检测。结果表明,缺失检出率为49．2％,66．4％的断裂点位于内含子44～52内,以内含子50为最多(14．8％),4对外显子引物的优化组合为外显子48、51、45和8,总检出率为41．7％;29例高危胎儿中9例男性胎儿为缺失型,缺失位点与先证者相同。通过首次对我国东北地区DMD／BMD患者筛查缺失发现dystrophin基因缺失主要分布于两个热区内,与国内其他地区比较外显子8附近区域可能是该地区缺失断裂的高发区;内含子44～52高度不稳定,其中内含子44的稳定性要高于中央缺失热区的稳定性,内含子50的不稳定性存在地区及种族差异;引物优化组合为检测患者及产前基因诊断提供了捷径,尤其是对散发家系是可行的并且有其优越性。     

Muscular Dystrophy in mdx Mice Despite Lack of Neuronal Nitric Oxide Synthase

Abstract: Neuronal nitric oxide synthase (nNOS) is a component of the dystrophin complex in skeletal muscle. The absence of dystrophin protein in Duchenne muscular dystrophy and in mdx mouse causes a redistribution of nNOS from the plasma membrane to the cytosol in muscle cells. Aberrant nNOS activity in the cytosol can induce free radical oxidation, which is toxic to myofibers. To test the hypothesis that derangements in nNOS disposition mediate muscle damage in Duchenne dystrophy, we bred dystrophin-deficient mdx male mice and female mdx heterozygote mice that lack nNOS. We found that genetic deletion of nNOS does not itself cause detectable pathology and that removal of nNOS does not influence the extent of increased sarcolemmal permeability in dystrophin-deficient mice. Thus, histological analyses of nNOS-dystrophin double mutants show pathological changes similar to the dystrophin mutation alone. Taken together, nNOS defects alone do not produce muscular dystrophy in the mdx model.     

Acetoacetate Accelerates Muscle Regeneration and Ameliorates Muscular Dystrophy in Mice

Acetoacetate (AA) is a ketone body and acts as a fuel to supply energy for cellular activity of various tissues. Here, we uncovered a novel function of AA in promoting muscle cell proliferation. Notably, the functional role of AA in regulating muscle cell function is further evidenced by its capability to accelerate muscle regeneration in normal mice, and it ameliorates muscular dystrophy in mdx mice. Mechanistically, our data from multiparameter analyses consistently support the notion that AA plays a non-metabolic role in regulating muscle cell function. Finally, we show that AA exerts its function through activation of the MEK1-ERK1/2-cyclin D1 pathway, revealing a novel mechanism in which AA serves as a signaling metabolite in mediating muscle cell function. Our findings highlight the profound functions of a small metabolite as signaling molecule in mammalian cells.     

Gene Expression and Polymorphism of Myostatin Gene and its Association with Growth Traits in Chicken

Myostatin is a member of TGF-β super family and is directly involved in regulation of body growth through limiting muscular growth. A study was carried out in three chicken lines to identify the polymorphism in the coding region of the myostatin gene through SSCP and DNA sequencing. A total of 12 haplotypes were observed in myostatin coding region of chicken. Significant associations between haplogroups with body weight at day 1, 14, 28, and 42 days, and carcass traits at 42 days were observed across the lines. It is concluded that the coding region of myostatin gene was polymorphic, with varied levels of expression among lines and had significant effects on growth traits. The expression of MSTN gene varied during embryonic and post hatch development stage.     

猪MSTN基因多态性及其SNPs的研究

双臀基因 (MSTN)在发育和成熟的骨骼肌中特异表达 ,并对肌肉具有负调控作用。采用PCR SSCP技术研究猪MSTN基因的第 2外显子和第 3外显子区域的DNA多态性。结果发现在两个外显子中均存在PCR SSCP多态性 ,在大白猪中 ,第 2外显子的多态性表现出 3种基因型 (CC、CT和TT) ;第 3外显子的多态性表现出两种基因型(AG和GG)。与猪生产性状进行相关性分析发现 :第 2外显子的多态性与生产性状基本无相关 ,第 3外显子的多态性与猪的背膘厚呈显著性相关 (P <0 0 5 ) ,与瘦肉率相关不显著 (P >0 0 5 )。对具DNA多态性的片段测序分析发现 :位于MSTN基因cDNA序列第 4 80处 (第 2外显子 )发生了单碱基的改变 (G→T)和第 10 0 8处 (第 3外显子 )发生单碱基的改变 (A→G) ,两处碱基的改变均没有导致氨基酸的变化 ,但第 10 0 8处碱基的改变 ,产生了ApaⅠ限制性内切酶位点 ,并建立了以ApaⅠ酶切位点的PCR RFLP分子标记技术     

Increase in decorin and biglycan in Duchenne Muscular Dystrophy: role of fibroblasts as cell source of these proteoglycans in the disease

Fibrosis is a common pathological feature observed in muscles of patients with Duchenne muscular dystrophy (DMD). Biglycan and decorin are small chondroitin/dermatan sulfate proteoglycans in the muscle extracellular matrix (ECM) that belong to the family of structurally related proteoglycans called small leucine-rich repeat proteins. Decorin is considered an anti-fibrotic agent, preventing the process by blocking TGF-beta activity. There is no information about their expression in DMD patients. We found an increased amount of both proteoglycans in the ECM of skeletal muscle biopsies obtained from DMD patients. Both biglycan and decorin were augmented in the perimysium of muscle tissue, but only decorin increased in the endomysium as seen by immunohistochemical analyses. Fibroblasts were isolated from explants obtained from muscle of DMD patients and the incorporation of radioactive sulfate showed an increased synthesis of both decorin and biglycan in cultured fibroblasts compared to controls. The size of decorin and biglycan synthesized by DMD and control fibroblasts seems to be similar in size and anion charge. These findings show that decorin and biglycan are increased in DMD skeletal muscle and suggest that fibroblasts would be, at least, one source for these proteoglycans likely playing a role in the muscle response to dystrophic cell damage.     

Muscle Stem Cells Give Rise to Rhabdomyosarcomas in a Severe Mouse Model of Duchenne Muscular Dystrophy

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