胰岛素样生长因子2的遗传学特征与生物学作用

胰岛素样生长因子（insulin-like growth factor,IGF）是一类多功能细胞增殖调控因子,因其化学结构与胰岛素相似而得名,IGF2是一个由67个氨基酸组成的蛋白质,它在胎儿发育、肿瘤细胞增殖、肌肉生长等方面具有重要的调控作用。本文主要论述了IGF2的基因结构、遗传方式,以及与印迹表达、肿瘤发生、肌纤维增殖和生长发育有关的生物学作用。 Abstract:Insulin-like growth factor (IGF) is multiple proliferation controlling factor of cells,and it gets this name according to its similarity to insulin.IGF2 is a single chain protein of 67 amino acids,which is probably required for normal fetal growth and development.In this article,we discussed the gene structure ,ways of its heredity ,and biological effects concerning imprinting,tumor development,muscle forming and individual growing of IGF2.     

The single nucleotide polymorphisms of the chicken myostatin gene are associated with skeletal muscle and adipose growth

Myostatin, a new member of the TGF-p superfamily, is predominantly expressed in skeletal muscle cells and functions as a negative regulator of skeletal muscle growth in animals. Recently, we have reported three single nucleotide polymorphisms (SNPs) in the chicken my-ostatin gene. Herein, we investigate the association of those SNPs with the production traits in a F2 chicken line derived from Broilers crossing to Silky with the least square analysis. The results show that the BB and AA genotypes are strongly associated with abdominal fat weight (AFW), abdominal fat percentage (AFP), and birth weight (BW) (P < 0.05). Breast muscle percentage (BMP) of the AA type is higher than that of the AB type. The breast muscle weight and breast muscle percentages of F2 individuals have significant difference between CC and DD genotypes (P< 0.05). Breast muscle weight (BMW) of EF birds is higher than that of EE birds (P< 0.05). In this report, we present the first genetic evidence to show that chicken myostatin not o     

Expression of basic fibroblast growth factor results in the decrease of myostatin mRNA in murine C2C12 myoblasts

During the development and regeneration of skeletal muscle,many growth factors,such asbasic fibroblast growth factor (bFGF,FGF-2) and myostatin,have been shown to play regulating roles.bFGF contributes to promote proliferation and to inhibit differentiation of skeletal muscle,whereas myostatinplays a series of contrasting roles.In order to elucidate whether the expression of bFGF has any relationshipwith the expression of myostatin in skeletal muscle cells,we constructed a eukaryotic expression vector forthe expression of exogenous bFGF in murine C2C12 myoblasts.Quantitative RT-PCR assays indicated thatwith the increase of the expression of exogenous bFGF gene,the expression of endogenous myostatin genewas suppressed at mRNA level and protein level.     

Preparation of polyclonal antibody specific for NOR1 and detection of its expression pattern in human tissues and nasopharyngeal carcinoma

Oxidored-nitro domain containing protein 1 （NORI） gene is a novel nitroreductase gene first isolated from nasopharyngeal carcinoma （NPC）. It plays an important role in the formation of chemical carcinogen and the carcinogenesis of NPC for its nitrosation function. Overexpression of the wild-type NOR1 gene in nasopharyngeal carcinoma cells is effective to inhibit cell growth and proliferation. In this study, for the first time, we generated a highly specific NOR1 antibody and analyzed NOR1 distribution in the human tissues and NPC biopsies. The results showed that NOR1 protein is predominantly expressed in human nasopharynx and tracheal tissues. Human heart, liver, spleen, stomach, colon, kidney, skeletal muscle, thymus, and pancreas are all deficient of NOR1 protein. More importantly, we performed immunohistochemistry assay of NOR1 protein expression in the NPC tissues, and the result showed that NOR1 protein is frequently down-expressed in NPC. These data shed light on the selectivity of potential physiological functions of NOR1 and provides an indispensable reference to the carcinogenesis process of NPC and to identify or validate tissue-specific drug targets.     

中华鳖7种组织SOX基因表达的RT-PCR分析

In this paper, RT PCR analysis on SOX gene of seven tissues from the Chinese soft shelled turtle (Pelodiscus sinensis) was studied, and SOX gene fragments of expression from the testicle, brain, heart, kidney and spleen were cloned using RT PCR products.The results show that SOX genes has specific expression in the testicle, brain, spleen, cardiac muscle and kidney and isn't expression in muscle, liver and ovary of femel.The results of sequence reveal that the SOX genes of expression in the testicle are TSSOX1、TSSOX4 TSSOX5 and TSSOX9, and those are TSSOX2 and TSSOX4 in the brain, and this is TSSOX4 in the spleen and heart tissue, and those are TSSOX2 and TSSOX3 in the kidney tissue.This suggests that the SOX gene act important role not only on the sex determination, but also on the development of neural system, immunocyte system and the differentiation of male germ cell.     

SDG714 Regulates Specific Gene Expression and Consequently Affects Plant Growth via H3K9 Dimethylation

Histone lysine methylation is known to be involved in the epigenetic regulation of gene expression in all eukaryotes including plants. Here we show that the rice SDG714 is primarily responsible for dimethylation but not trimethylation on histone H3K9 in vivo. Overexpression of YFP-SDG714 in Arabidopsis significantly inhibits plant growth and this inhibition is associated with an enhanced level of H3K9 dimethylation. Our microarray results show that many genes essential for the plant growth and development were downregulated in transgenic Arabidopsis plants overexpressing YFP-SDG714. By chromatin immunoprecipitation analysis, we show that YFP-SDG714 is targeted to specific chromatin regions and dimethylate the H3K9, which is linked with heterochromatinization and the downregulation of genes. Most interestingly, when YFP-SDG714 production is stopped, the inhibited plants can partially restore their growth, suggesting that the perturbation of gene expression caused by YFP-SDG714 is revertible. Taken together, our results point to an important role of SDG714 in H3K9 dimethylation, suppression of gene expression and plant growth, and provide a potential method to regulate gene expression and plant development by an on-off switch of SDG714 expression.     

Molecular characterization of the BTG2 and BTG3 genes in fetal muscle development of pigs

BTG2 and BTG3 are two members of the B-cell translocation gene family with anti-proliferative properties. BTG1 gene in this gene family has been reported to play a key role in muscle growth. In this study, we identified and characterized the porcine BTG2 and BTG3 genes, mapped the two genes to porcine chromosomes, and analyzed their expression differences in the longissimus dorci muscle of 33 dpc (day postconception), 65 dpc and 90 dpc in the lean Landrace and fatty Chinese Tongcheng pig breeds. Expression changes in differentiated C2C12 cells were also investigated with myogenin as internal control. The results showed that the porcine BTG2 and BTG3 genes were mapped on SSC9q21-25 and SSC13q47, respectively. BTG2 gene expressed at high levels in skeletal muscle and heart in both Tongcheng and Landrace pigs whereas BTG3 gene expressed at lower levels in skeletal muscle and heart than in other tissues. Furthermore, BTG3 expressed at higher levels in skeletal muscle of Tonghceng compared with Landrace pig. The expression of BTG2 and BTG3 was significantly different in skeletal muscle among different developmental stages and between the two breeds. Expression analysis in murine myoblast cells showed that both genes were induced in differentiated C2C12 cells, suggesting a role of them in myogenic differentiation. Our study indicated that BTG2 and BTG3, especially BTG3 gene, may be important genes for skeletal muscle growth.     

生长激素基因的克隆和表达及其对贵州地方黄牛骨骼肌细胞增殖的影响

本研究旨在探究生长激素(Growth hormone,GH)对贵州地方黄牛骨骼肌细胞增殖的表达调控,探明超表达GH基因对骨骼肌细胞增殖的影响.首先利用反转录PCR扩增黄牛GH基因的蛋白质编码区(Coding sequence,CDS),将其克隆至pUCM-T载体,并连接转化构建超表达载体pEGFP-N3-GH.同时使用...     

肌肉生长抑制素调控动物骨骼肌生长机制的研究进展

肌肉生成抑制素（myostatin, MSTN）在动物机体骨骼肌的增殖、分化和生长中起着重要的负调控作用。MSTN基因的过表达会阻碍骨骼肌增殖分化及生长发育,而缺失或表达降低则会导致肌肉肥大,形成双肌现象（double muscle phenomenon, DMP）。MSTN能作用于多个基因及结合多种细胞因子广泛参与生理生化、物质代谢、病理调控等过程,在动物机体生长发育过程中扮演着重要的角色。本文将从MSTN基因的历史渊源、基因定位、时空表达特性、部分相关作用机制等方面进行论述,旨在对MSTN调控动物骨骼肌生长部分机制作梳理,以期为后期研究提供理论依据。     

The RYR1 g.1843C>T mutation is associated with the effect of the IGF2 intron3-g.3072G>A mutation on muscle hypertrophy

Muscle growth is a complex phenomenon regulated by many factors, whereby net growth results from the combined action of synthesis and turnover. In pigs, two quantitative trait nucleotides (QTN) are known to have an important influence on muscle growth and fat deposition: one QTN is located in the ryanodine receptor 1 (RYR1) gene (RYR1 g.1843C>T) and the other, a paternally expressed QTN, is in the insulin-like growth factor 2 (IGF2) gene (IGF2 intron3-g.3072G>A). The mutation in IGF2 abrogates in vitro interaction with a repressor, which leads to a threefold increase of IGF2 expression in post-natal muscle. The family of the calpains, a family of Ca(2+)-sensitive muscle endopeptidases, and their specific inhibitor calpastatin play an important role in post-natal protein degradation, also influencing muscle and carcass traits. This study investigated the possible interactions between the genotypes of the RYR1 and IGF2 QTN on IGF2 expression. Samples were taken from several muscles and from pigs at several ages, and messenger RNA expression levels were measured using a real-time quantification assay. IGF2 expression in m. longissimus dorsi of animals with mutations in both IGF2 and RYR1 was significantly lower than in animals that inherited the IGF2 mutation but were homozygous wildtype for RYR1.     

An SNP in the MyoD1 Gene Intron 2 Associated with Growth and Carcass Traits in Three Duck Populations

Myogenic differentiation 1 (MyoD1) genes belong to the MyoD gene family and play key roles in growth and muscle development. This study was designed to investigate the effects of variants in the MyoD1 gene on duck growth and carcass traits. Three duck populations (Cherry Valley, Jingjiang, and Muscovy) were sampled, their growth and carcass traits were measured, and they were genotyped using the PCR–RFLP method. The results showed one novel polymorphism, an alteration in intron 2 of the MyoD1 gene (A to T). It was associated with the traits of weight at 8?weeks, carcass weight, breast muscle weight, leg muscle weight, eviscerated percentage, percentage of leg muscle weight, dressing percentage, and lean meat percentage. This alteration in intron 2 of MyoD1 may be linked with potential major loci or genes affecting some growth and carcass traits.     

Pleiotrophin Gene Therapy for Peripheral Ischemia: Evaluation of Full-Length and Truncated Gene Variants

Pleiotrophin (PTN) is a growth factor with both pro-angiogenic and limited pro-tumorigenic activity. We evaluated the potential for PTN to be used for safe angiogenic gene therapy using the full length gene and a truncated gene variant lacking the domain implicated in tumorigenesis. Mouse myoblasts were transduced to express full length or truncated PTN (PTN or T-PTN), along with a LacZ reporter gene, and injected into mouse limb muscle and myocardium. In cultured myoblasts, PTN was expressed and secreted via the Golgi apparatus, but T-PTN was not properly secreted. Nonetheless, no evidence of uncontrolled growth was observed in cells expressing either form of PTN. PTN gene delivery to myocardium, and non-ischemic skeletal muscle, did not result in a detectable change in vascularity or function. In ischemic hindlimb at 14 days post-implantation, intramuscular injection with PTN-expressing myoblasts led to a significant increase in skin perfusion and muscle arteriole density. We conclude that (1) delivery of the full length PTN gene to muscle can be accomplished without tumorigenesis, (2) the truncated PTN gene may be difficult to use in a gene therapy context due to inefficient secretion, (3) PTN gene delivery leads to functional benefit in the mouse acute ischemic hindlimb model.