GENE REGULATION IN CARDIAC ASSIST SKELETAL MUSCLE

心脏辅助骨骼肌的基因调控

• 批准号: 3365052
• 负责人: FRED N BRIGGS
• 金额: $ 22.93万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-04-01 至 1997-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3365052
• 关键词: DNA footprinting; adenosinetriphosphatase; beta adrenergic agent; beta adrenergic receptor; cyclic AMP; dogs; electrostimulus; gene expression; genetic enhancer element; genetic regulation; genetic regulatory element; genetic transcription; genetic translation; heart failure; heart function; immunochemistry; muscle contraction; muscle proteins; myocardium; myofibrils; nucleic acid probes; protein structure; receptor expression; sarcoplasmic reticulum; striated muscles; transcription factor

When the canine latissimus dorsi is conditioned, for the purpose of using it to support the failing myocardium, muscle fiber type is switched from predominantly fast-twitch type to completely slow-twitch type. Although it is well established that electro-stimulation transforms myofilament proteins, i.e. leads to the suppression of genes for fast-twitch myofilament proteins to the expression of slow-twitch myofilament genes; the possibility that sarcoplasmic reticulum (SR) proteins undergo a similar switch has only recently been recognized [Briggs et al., 1990]. This proposed research program is designed to: 1) determine the effect of this switch in SR protein isoforms on mechanical performance; 2) use the information gained from the switch to optimize stimulus parameters and to support the use of beta-agonist; and 3) examine the mechanisms regulating the expression of the genes for the slow-twitch SR proteins. Since the designations, slow-twitch and fast-twitch, refer primarily to the duration of the twitch, which is primarily a function of the SR Ca-ATPase, the time course of the switch from the fast-twitch type Ca-ATPase isoform to the slow-twitch ca-ATPase isoform will be compared to switches in mechanical performance. The contractile properties of the conditioned muscle to be studied are: twitch time, relaxation rate, fusion frequency, and tetanus to twitch ratio; all properties affected by proteins in the SR. Also to be examined are the effect of beta-agonist on the function of the conditioned muscle because the Ca-ATPase of slow-twitch muscle is regulated in part by the SR protein, phospholamban. A search for changes in beta receptor density in conditioned muscle could provide a rationale for the use of beta-agonist to improve the contractility of the wrapped muscle. The role of gene regulation in switching isoforms will be studied at the transcriptional and translational level. Transcriptional regulation of gene expression will be studied by measuring, at various times after the initiation of chronic stimulation, mRNA isoform levels and rate of transcription by nuclear run-on assays. A full length Ca-ATPase gene will be used as starting material for experiments: 1) to identify cis enhancer regions, and 2) to identify nuclear proteins (transcription factors) with affinities for those enhancer sites. The possibility that cyclic-AMP or inositol trisphosphate are signals for gene switching will be investigated.

当犬latissimus redorsi的条件时，目的是 为了支持失败的心肌，肌肉纤维类型从 主要是快速打type类型，完全慢速交换类型。 虽然是 已经很好地确定电刺激会改变肌丝 蛋白质，即导致基因抑制快速开关 肌丝蛋白表达慢骨肌丝基因的表达； 肌浆网（SR）蛋白发生类似的可能性 开关直到最近才被认识到[Briggs等，1990]。 这 拟议的研究计划旨在：1）确定此效果 在机械性能上转换SR蛋白同工型； 2）使用 从开关获得的信息以优化刺激参数和到 支持使用β-激动剂； 3）检查调节的机制 慢速Twitch SR蛋白的基因的表达。 自从 名称，慢速交通和快速交换，主要是指持续时间 Twitch的主要是SR CA-ATPase的函数 从快速打开类型的CA-ATPase同工型到开关的过程 将慢速交换CA-ATPase同工型与机械开关进行比较 表现。 条件肌肉的收缩特性为 研究的是：抽搐时间，放松率，融合频率和破伤风 与抽搐比； SR中受蛋白质影响的所有特性。 也是 检查的是β-激动剂对条件功能的影响 肌肉是因为慢速肌肉的CA-ATPase部分受 SR蛋白，磷脂。 搜索β受体的变化 条件肌肉的密度可以为使用的理由提供理由 β激动剂提高包裹肌肉的收缩力。 角色 将研究开关同工型中的基因调节 转录和翻译水平。 转录调节 在测量之后的不同时间测量基因表达 慢性刺激的启动，mRNA同工型水平和速率 通过核跑步测定法转录。 全长Ca-ATPase基因将 用作实验的起始材料：1）识别CIS增强剂 区域，以及2）确定具有的核蛋白质（转录因子） 这些增强器站点的亲和力。 环状AMP或 肌醇三磷酸盐是基因转换的信号。