. The long term goal of the laboratory is to elucidate the cellular, molecular and genetic mechanisms that regulate myocardial cell differentiation and myofibrillogenesis in the developing heart. Ambystoma mixicanum is an intriguing model for studying heart development because it carries a mutation in gene c thought tot exert its effect via abnormal inductive processes from the anterior endoderm. The hearts of double recessive (c/c) mutant embryos do not beat, as they are deficient in tropomyosin and do not contain organized myofibrils. However, the defect can be corrected by culturing the mutant hearts in the presence of normal anterior endoderm tissue, medium conditioned by the anterior endoderm, or total RNA isolated from endoderm or the conditioned medium, each of which promotes myofibrillogenesis in the mutant hearts. A single clone (#4) has been identified from a cDNA library constructed from total conditioned medium RNA which can act as a template for the bioactive RNA capable of correcting the heart defect in organ culture as well as in vivo. The bioactive RNA can bind with a protein present in the embryonic axolotl heart and the bioactive RNA enters the cells of mutant hearts to effect rescue. It is hypothesized that the bioactive RNA is a regulatory molecules which up regulates tropomyosin synthesis in the mutant hearts for promoting myofibrillogenesis either directly or in complex with its binding protein. There are four Specific Aims to test this hypothesis: 1) The expression of the bioactive RNA will be examined in normal and mutant hearts at various stages of development using RT-PCR and in situ hybridization. Ectopic expression of sense and antisense RNA will be tested by creating transgenic axolotls; 2) In vitro mutagenesis of the clone #4 RNA will be performed to elucidate the mechanism of its rescuing activity as well as its binding ability to the newly-discovered binding protein; 3) Study up regulation of tropomyosin in the mutant hearts corrected by the cone #4 RNA; 4) The full length cDNA and the RNA and its mechanism by which its expression is regulated. It is anticipated that these studies will provide significant new information the mechanism of in vivo inductive interactions responsible for normal cardiac myocyte differentiation at the molecular level.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL061246-04
Application #
6165082
Study Section
Special Emphasis Panel (ZRG4-PHRA (03))
Program Officer
Wang, Lan-Hsiang
Project Start
1998-03-15
Project End
2001-07-01
Budget Start
2001-03-01
Budget End
2001-07-01
Support Year
4
Fiscal Year
2001
Total Cost
$15,080
Indirect Cost
Name
Texas A&M University
Department
Physiology
Type
Schools of Medicine
DUNS #
City
College Station
State
TX
Country
United States
Zip Code
77845
Kochegarov, Andrei; Moses-Arms, Ashley; Lemanski, Larry F (2015) A fetal human heart cardiac-inducing RNA (CIR) promotes the differentiation of stem cells into cardiomyocytes. In Vitro Cell Dev Biol Anim 51:739-48
Moses-Arms, Ashley; Kochegarov, Andrei; Arms, Jedidiah et al. (2015) Identification of a human mitochondrial RNA that promotes tropomyosin synthesis and myocardial differentiation. In Vitro Cell Dev Biol Anim 51:273-80
Kochegarov, Andrei; Moses, Ashley; Lian, William et al. (2013) A new unique form of microRNA from human heart, microRNA-499c, promotes myofibril formation and rescues cardiac development in mutant axolotl embryos. J Biomed Sci 20:20
Jia, Pingping; Zhang, Chi; Jia, Yuanyuan et al. (2011) Identification of a truncated form of Methionine Sulfoxide Reductase A expressed in mouse embryonic stem cells. J Biomed Sci 18:46
Zhang, Chi; Jia, Pingping; Jia, Yuanyuan et al. (2011) Anoxia, acidosis, and intergenic interactions selectively regulate methionine sulfoxide reductase transcriptions in mouse embryonic stem cells. J Cell Biochem 112:98-106
Zhang, Chi; Jia, Pingping; Jia, Yuanyuan et al. (2010) Methionine sulfoxide reductase A (MsrA) protects cultured mouse embryonic stem cells from H2O2-mediated oxidative stress. J Cell Biochem 111:94-103
Zhang, Chi; Jia, Pingping; Huang, Xupei et al. (2009) Myofibril-inducing RNA (MIR) is essential for tropomyosin expression and myofibrillogenesis in axolotl hearts. J Biomed Sci 16:81
Jia, P; Zhang, C; Huang, X P et al. (2008) A novel protein involved in heart development in Ambystoma mexicanum is localized in endoplasmic reticulum. J Biomed Sci 15:789-99
Zhang, C; Pietras, K M; Sferrazza, G F et al. (2007) Molecular and immunohistochemical analyses of cardiac troponin T during cardiac development in the Mexican axolotl, Ambystoma mexicanum. J Cell Biochem 100:1-15
Sferrazza, Gian Franco; Zhang, Chi; Jia, Pingping et al. (2007) Role of myofibril-inducing RNA in cardiac TnT expression in developing Mexican axolotl. Biochem Biophys Res Commun 357:32-7

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