Ribosome specialization in adult skeletal muscle

成人骨骼肌的核糖体特化

• 批准号: 8822451
• 负责人: JOHN Joseph MCCARTHY
• 金额: $ 16.4万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8822451
• 关键词: Ablation; Acquired Immunodeficiency Syndrome; Adult; Affect; Aging; Applications Grants; Atrophic; Biological Assay; Cachexia; Cells; Chronic; Clinical; Data; Databases; Deterioration; Development; Disease; EMSA; Embryonic Development; Future; Gene Expression; Gene Expression Regulation; Genes; Genetic Translation; Goals; Growth; HIV; Health; Heart failure; Heterogeneity; Housekeeping; Immobilization; In Vitro; Internal Ribosome Entry Site; Limb structure; Malignant Neoplasms; Mammals; Mediating; Messenger RNA; MicroRNAs; Molecular; Molecular Profiling; Morbidity - disease rate; Mus; Muscle; Muscle Fibers; Muscle function; Mutagenesis; Myogenic Regulatory Factors; Nature; Pattern; Peptidyltransferase; Play; Process; Proteins; Quality of life; Reading; Regulation; Reporter; Repression; Rheumatoid Arthritis; Ribosomal Frameshifting; Ribosomal Proteins; Ribosomes; Risk; Role; Sepsis; Skeletal Muscle; Striated Muscles; System; Systemic disease; Terminator Codon; Testing; Tetanus Helper Peptide; Tissues; Transcript; Transfer RNA; Translating; Translations; Untranslated Regions; base; effective therapy; indexing; interest; loss of function; mortality; muscle form; muscle hypertrophy; neurotensin mimic 1; novel; patient population; prevent; programs; promoter; public health relevance; research study; response; ribosomal protein L3; sarcopenia; skeletal muscle plasticity

DESCRIPTION (provided by applicant): The ribosome has generally been considered to have no cell-specific function but rather serves in a "housekeeping" capacity. This view has been challenged by evidence showing heterogeneity in the protein composition of the ribosome, resulting in the functional specialization of the ribosome. Ribosome specialization alters the intrinsic translational activity of the ribosome thereby affecting the translation of a particular et of mRNAs. Expression profiling of ribosomal proteins in adult tissues showed that ribosomal protein L3 (Rpl3) is highly expressed in all tissues except in striated muscle; in contrast, the expression of the Rpl3-like is exactly the opposite, being highly expressed only in striated muscle, skeletal muscle in particular. Preliminary data revealed that during periods of significant muscle hypertrophy, such as post-natal development and in response to synergist ablation, the expression pattern of these two genes is completely reversed such that Rpl3 is highly-expressed and Rpl3-like is dramatically down-regulated in skeletal muscle. Consistent with these observations, we found that over-expression of RPL3-like promotes significant myotube atrophy associated with a lower fusion index. While Rpl3 is necessary for ribosome assembly and peptidyl transferase activity of the ribosome, the ribosomal function of Rpl3-like remains completely unknown. Based on our preliminary data, we hypothesize that Rpl3-like acts to limit muscle size by altering the intrinsic translational activity of skeletal muscle ribosomes. To test the idea of ribosome specialization in skeletal muscle and its regulation, the following objectives will be pursued: 1) Determine how muscle-specific Rpl3-like alters ribosome function and 2) Determine the mechanisms regulating the muscle-specific pattern of expression of Rpl3 and Rpl3-like. We have developed a Tet-On system to compare translational fidelity of ribosomes containing Rpl3 versus Rpl3- like. Ribosome function will be examined by assessing programmed ribosomal frameshifting, stop codon read- through, near- and non-cognate tRNA utilization and IRES-mediated translation. Based on preliminary data, we will test the hypothesis that the muscle-specific microRNA-1 represses Rpl3 expression in skeletal muscle by using 32-UTR reporter assay with mutagenesis in gain- and loss-of-function studies using miR-1 mimic and antimiR, respectively. Next, we will test the hypothesis that MyoD regulates the muscle-specific expression of Rpl3-like through promoter analysis, mutagenesis, EMSA and ChIP assay. The fact that there is a muscle- specific Rpl3 strongly suggests ribosomes have become specialized in skeletal muscle - understanding why this is so is the long-term goal of this project In the short-term, the goal is to better understand the function and regulation of Rpl3-like as the basis for a future R01 grant application investigating the role of ribosome specialization in skeletal muscle plasticity and disease.

描述（由申请人提供）：核糖体通常被认为没有细胞特异性功能，而是具有“管家”功能。这一观点受到了证据的挑战，证据显示核糖体蛋白质组成的异质性，导致核糖体的功能特化。核糖体特化改变了核糖体的内在翻译活性，从而影响了一组特定mrna的翻译。成人组织中核糖体蛋白的表达谱显示，核糖体蛋白L3 （Rpl3）在除横纹肌外的所有组织中均高表达；而rpl3样蛋白的表达则完全相反，仅在横纹肌，尤其是骨骼肌中高表达。初步数据显示，在重大时期