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Li Y, Zhou T, Zhuang J, Dai Y, Zhang X, Bai S, Zhao B, Tang X, Wu X, Chen Y. Effects of feeding restriction on skeletal muscle development and functional analysis of TNNI1 in New Zealand white rabbits. Anim Biotechnol 2023; 34:4435-4447. [PMID: 36520026 DOI: 10.1080/10495398.2022.2155662] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
While restricting nutrition can improve diseases related to the digestive tract, excessive restriction of food intake can also lead to malnutrition and delayed physical growth. Therefore, this brings the demand to study the effect and potential mechanism of restricted feeding on skeletal muscle development in rabbits. This study utilized hematoxylin-eosin (HE) staining to detect muscle fiber area which depicted significant reduction in skeletal muscle fiber upon 30% feed restriction (p < 0.05). The control group and 30% feed restricted group showed 615 deferentially expressed genes (DEGs). Through the GO and KEGG functional enrichment analysis demonstrated 28 DEGs related to muscle development. KEGG analysis showed enrichment of pathways including PI3K/Akt signaling pathway, MAPK signaling pathway, and Hedgehog signaling pathway. Further, the full length of troponin I1, slow skeletal type (TNNI1) was cloned. We studied the expression of skeletal muscle differentiation-related genes such as MyoD, Myf5 gene and Desmin. Specifically, the TNNI1 gene overexpression and knockdown studies were conducted. The over-expression of TNNI1 significantly enhanced the expression of the skeletal muscle development-related genes. Contrastingly, the silencing of TNNI1 gene reduced the expression significantly. These findings showed that TNNI1 may be a regulator for regulating the expression of muscle development-related genes.
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Affiliation(s)
- Yunpeng Li
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
| | - Tong Zhou
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
| | - Junyi Zhuang
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
| | - Yingying Dai
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
| | - Xiyu Zhang
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
| | - Shaocheng Bai
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
| | - Bohao Zhao
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
| | - Xianwei Tang
- Jiangsu Pizhou Orient Breeding Co., Ltd, Jiangsu, China
| | - Xinsheng Wu
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
| | - Yang Chen
- College of Animal Science and Technology, Yangzhou University, Jiangsu, China
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Pan B, Xu ZW, Xu Y, Liu LJ, Zhu J, Wang X, Nan C, Zhang Z, Shen W, Huang XP, Tian J. Diastolic dysfunction and cardiac troponin I decrease in aging hearts. Arch Biochem Biophys 2016; 603:20-8. [PMID: 27184165 DOI: 10.1016/j.abb.2016.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 05/07/2016] [Accepted: 05/11/2016] [Indexed: 11/28/2022]
Abstract
Cardiac tropnoin I (cTnI) plays a critical role in the regulation of diastolic function, and its low expression may result in cardiac diastolic dysfunction, which is the most common form of cardiovascular disorders in older adults. In this study, cTnI expression levels were determined in mice at various ages and cardiac function was measured and compared between young adult mice (3 and 10 months) and older mice (18 months). The data indicated that the cTnI levels reached a peak high in young adult hearts (3 months), but decreased in older hearts (18 months). Furthermore, the older hearts showed a significant diastolic dysfunction observed by P-V loop and echocardiography measurements. To further define the mechanism underlying the cTnI decrease in aging hearts, we tested DNA methylation and histone acetylation modifications of cTnI gene. We found that acetylation of histone near the promoter region of cTnI gene played an important role in regulation of cTnI expression in the heart at different ages. Our study indicates that epigenetic modification caused cTnI expression decrease is one of the possible causes that result in a reduced cTnI level and diastolic dysfunction in the older hearts.
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Affiliation(s)
- B Pan
- Heart Centre, Children's Hospital of Chongqing Medical University, Chongqing, PR China; Key Laboratory of Developmental Disease in Childhood (Chongqing Medical University), Ministry of Education, Chongqing, PR China; Key Laboratory of Pediatrics in Chongqing, PR China; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, PR China
| | - Z W Xu
- Heart Centre, Children's Hospital of Chongqing Medical University, Chongqing, PR China; Key Laboratory of Developmental Disease in Childhood (Chongqing Medical University), Ministry of Education, Chongqing, PR China; Key Laboratory of Pediatrics in Chongqing, PR China; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, PR China
| | - Y Xu
- Heart Centre, Children's Hospital of Chongqing Medical University, Chongqing, PR China; Key Laboratory of Developmental Disease in Childhood (Chongqing Medical University), Ministry of Education, Chongqing, PR China; Key Laboratory of Pediatrics in Chongqing, PR China; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, PR China
| | - L J Liu
- Key Laboratory of Developmental Disease in Childhood (Chongqing Medical University), Ministry of Education, Chongqing, PR China; Key Laboratory of Pediatrics in Chongqing, PR China; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, PR China
| | - J Zhu
- Key Laboratory of Developmental Disease in Childhood (Chongqing Medical University), Ministry of Education, Chongqing, PR China; Key Laboratory of Pediatrics in Chongqing, PR China; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, PR China
| | - X Wang
- Department of Biomedical Science, Charlie E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - C Nan
- Department of Biomedical Science, Charlie E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Z Zhang
- Department of Biomedical Science, Charlie E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - W Shen
- Department of Biomedical Science, Charlie E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - X P Huang
- Department of Biomedical Science, Charlie E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA.
| | - J Tian
- Heart Centre, Children's Hospital of Chongqing Medical University, Chongqing, PR China.
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Abstract
Cardiac gene expression regulation is controlled not only by genetic factors but also by environmental, i.e., epigenetic factors. Several environmental toxic effects such as oxidative stress and ischemia can result in abnormal myofibril gene expression during heart development. Troponin, one of the regulatory myofibril proteins in the heart, is a well-known model in study of cardiac gene regulation during the development. In our previous studies, we have demonstrated that fetal form troponin I (ssTnI) expression in the heart is partially regulated by hormones, such as thyroid hormone. In the present study, we have explored the epigenetic role of histone modification in the regulation of ssTnI expression. Mouse hearts were collected at different time of heart development, i.e., embryonic day 15.5, postnatal day 1, day 7, day 14 and day 21. Levels of histone H3 acetylation (acH3) and histone H3 lysine 9 trimethylation (H3K9me(3)) were detected using chromatin immunoprecipitation assays in slow upstream regulatory element (SURE) domain (TnI slow upstream regulatory element), 300-bp proximal upstream domain and the first intron of ssTnI gene, which are recognized as critical regions for ssTnI regulation. We found that the levels of acH3 on the SURE region were gradually decreased, corresponding to a similar decrease of ssTnI expression in the heart, whereas the levels of H3K9me(3) in the first intron of ssTnI gene were gradually increased. Our results indicate that both histone acetylation and methylation are involved in the epigenetic regulation of ssTnI expression in the heart during the development, which are the targets for environmental factors.
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Xu Y, Liu L, Pan B, Zhu J, Nan C, Huang X, Tian J. DNA methylation regulates mouse cardiac myofibril gene expression during heart development. J Biomed Sci 2015; 22:88. [PMID: 26475623 PMCID: PMC4609054 DOI: 10.1186/s12929-015-0203-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/09/2015] [Indexed: 12/31/2022] Open
Abstract
Background It is well known that epigenetic modifications play an important role in controlling the regulation of gene expression during the development. Our previous studies have demonstrated that the expression of fetal troponin I gene (also called slow skeletal troponin I, ssTnI) is predominated in the fetal stage, reduced after birth and disappeared in the adulthood. The mechanism underlying the developmentally related ssTnI gene regulation is not clear. In this study, we have explored the epigenetic role of DNA methylation in the regulation of ssTnI expression in the heart during the development. Results The DNA methylation levels of CpG island and CpG dinucleotides region were detected using methylation specific PCR (MSP) and bisulfite sequence PCR (BSP) in 2000 bp upstream and 100 bp upstream of ssTnI gene promoter. Real time RT-PCR and Western blot were used to detect ssTnI mRNA and protein expression levels. We found that DNA methylation levels of the CpG dinucleotides region in ssTnI gene promoter were increased with the development, corresponding to a decreased expression of ssTnI gene in mouse heart. However the DNA methylation levels of CpG islands in this gene were not changed during the development. Application of a methylation inhibitor, 5-Azacytidine, in cultured myocardial cells partially prevented the decline of ssTnI expression. Conclusion Our results indicate that DNA methylation, as an epigenetic intervention, plays a role in the regulation of the fetal TnI gene expression in the heat during the development.
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Affiliation(s)
- Yang Xu
- Department of Cardiology, Heart Centre, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2nd Road, Yu Zhong District, Chongqing, 400014, P.R. of China
| | - Lingjuan Liu
- Department of Cardiology, Heart Centre, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2nd Road, Yu Zhong District, Chongqing, 400014, P.R. of China.,Ministry of Education Key Laboratory of Child Development and Disorders; Key Laboratory of Pediatrics in Chongqing, CSTC2009CA5002; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, P.R. of China
| | - Bo Pan
- Department of Cardiology, Heart Centre, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2nd Road, Yu Zhong District, Chongqing, 400014, P.R. of China
| | - Jing Zhu
- Ministry of Education Key Laboratory of Child Development and Disorders; Key Laboratory of Pediatrics in Chongqing, CSTC2009CA5002; Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, P.R. of China
| | - Changlong Nan
- Department of Biomedical Science, Charlie E. Schmidt College of Medicine, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Xupei Huang
- Department of Biomedical Science, Charlie E. Schmidt College of Medicine, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA.
| | - Jie Tian
- Department of Cardiology, Heart Centre, Children's Hospital of Chongqing Medical University, 136 Zhongshan 2nd Road, Yu Zhong District, Chongqing, 400014, P.R. of China.
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Li Y, Fang J, Hua Y, Wang C, Mu D, Zhou K. The study of fetal rat model of intra-amniotic isoproterenol injection induced heart dysfunction and phenotypic switch of contractile proteins. BIOMED RESEARCH INTERNATIONAL 2014; 2014:360687. [PMID: 25136580 PMCID: PMC4127273 DOI: 10.1155/2014/360687] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 05/31/2014] [Accepted: 06/20/2014] [Indexed: 11/29/2022]
Abstract
To establish a reliable isoproterenol induced heart dysfunction fetal rat model and understand the switches of contractile proteins, 45 pregnant rats were divided into 15 mg/kg-once, 15 mg/kg-twice, sham-operated once, sham-operated twice, and control groups. And 18 adult rats were divided into isoproterenol-treated and control groups. H&E staining, Masson staining, and transmission electron microscope were performed. Apoptotic rate assessed by TUNEL analysis and expressions of ANP, BNP, MMP-2, and CTGF of hearts were measured. Intra-amniotic injections of isoproterenol were supplied on E14.5 and E15.5 for fetuses and 7-day continuous intraperitoneal injections were performed for adults. Then echocardiography was performed with M-mode view assessment on E18.5 and 6 weeks later, respectively. Isoproterenol twice treated fetuses exhibited significant changes in histological evaluation, and mitochondrial damages were significantly severe with increased apoptotic rate. ANP and BNP increased and that of MMP-2 increased in isoproterenol twice treated group compared to control group, without CTGF. The isoforms transition of troponin I and myosin heavy chain of fetal heart dysfunction were opposite to adult procedure. The administration of intra-amniotic isoproterenol to fetal rats could induce heart dysfunction and the regulation of contractile proteins of fetuses was different from adult procedure.
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Affiliation(s)
- Yifei Li
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, No. 20, 3rd Section, South Renmin Road, Chengdu, Sichuan 610041, China
| | - Jie Fang
- West China Stomatology School, Sichuan University, Chengdu, Sichuan 610041, China
| | - Yimin Hua
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, No. 20, 3rd Section, South Renmin Road, Chengdu, Sichuan 610041, China
- Ministry of Education Key Laboratory of Women and Children's Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Chuan Wang
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, No. 20, 3rd Section, South Renmin Road, Chengdu, Sichuan 610041, China
- Ministry of Education Key Laboratory of Women and Children's Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Dezhi Mu
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, No. 20, 3rd Section, South Renmin Road, Chengdu, Sichuan 610041, China
- Ministry of Education Key Laboratory of Women and Children's Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Kaiyu Zhou
- Department of Pediatric Cardiovascular Disease, West China Second University Hospital, Sichuan University, No. 20, 3rd Section, South Renmin Road, Chengdu, Sichuan 610041, China
- Ministry of Education Key Laboratory of Women and Children's Diseases and Birth Defects, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, China
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Expression of sarcomeric tropomyosin in striated muscles in axolotl treated with shz-1, a small cardiogenic molecule. Cardiovasc Toxicol 2014; 15:29-40. [PMID: 24958154 DOI: 10.1007/s12012-014-9265-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We evaluated the effect of shz-1, a cardiogenic molecule, on the expression of various tropomyosin (TM) isoforms in the Mexican axolotl (Ambystoma mexicanum) hearts. qRT-PCR data show a ~1.5-fold increase in cardiac transcripts of the Nkx2.5 gene, which plays a crucial role in cardiogenesis in vertebrates. Shz-1 augments the expression of transcripts of the total sarcomeric TPM1 (both TPM1α & TPM1κ) and sarcomeric TPM4α. In order to understand the mechanism by which shz-1 augments the expression of sarcomeric TPM transcription in axolotl hearts, we transfected C2C12 cells with pGL3.axolotl. We transfected C2C12 cells with pGL3-axolotl TPM4 promoter constructs containing the firefly luciferase reporter gene. The transfected C2C12 cells were grown in the absence or presence of shz-1 (5 μM). Subsequently, we determined the firefly luciferase activity in the extracts of transfected cells. The results suggest that shz-1 activates the axolotl TPM4 promoter-driven ectopic expression in C2C12 cells. Also, we transfected C2C12 cells with a pGL3.1 vector containing the promoter of the mouse skeletal muscle troponin-I and observed a similar increase in the luciferase activity in shz-1-treated cells. We conclude that shz-1 activates the promoters of a variety of genes including axolotl TPM4. We have quantified the expression of the total sarcomeric TPM1 and observed a 1.5-fold increase in treated cells. Western blot analyses with CH1 monoclonal antibody specific for sarcomeric isoforms show that shz-1 does not increase the expression of TM protein in axolotl hearts, whereas it does in C2C12 cells. These findings support our hypothesis that cardiac TM expression in axolotl undergoes translational control.
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Ku PM, Chen LJ, Liang JR, Cheng KC, Li YX, Cheng JT. Molecular role of GATA binding protein 4 (GATA-4) in hyperglycemia-induced reduction of cardiac contractility. Cardiovasc Diabetol 2011; 10:57. [PMID: 21702924 PMCID: PMC3141394 DOI: 10.1186/1475-2840-10-57] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 06/24/2011] [Indexed: 01/10/2023] Open
Abstract
Background Diabetic cardiomyopathy, a diabetes-specific complication, refers to a disorder that eventually leads to left ventricular hypertrophy in addition to diastolic and systolic dysfunction. In recent studies, hyperglycemia-induced reactive oxygen species (ROS) in cardiomyocytes have been linked to diabetic cardiomyopathy. GATA binding protein 4 (GATA-4) regulates the expression of many cardio-structural genes including cardiac troponin-I (cTnI). Methods Streptozotocin-induced diabetic rats and H9c2 embryonic rat cardiomyocytes treated with a high concentration of glucose (a D-glucose concentration of 30 mM was used and cells were cultured for 24 hr) were used to examine the effect of hyperglycemia on GATA-4 accumulation in the nucleus. cTnI expression was found to be linked to cardiac tonic dysfunction, and we evaluated the expression levels of cTnI and GATA-4 by Western blot analysis. Results Cardiac output was lowered in STZ-induced diabetic rats. In addition, higher expressions of cardiac troponin I (cTnI) and phosphorylated GATA-4 were identified in these rats by Western blotting. The changes were reversed by treatment with insulin or phlorizin after correction of the blood sugar level. In H9c2 cells, ROS production owing to the high glucose concentration increased the expression of cTnI and GATA-4 phosphorylation. However, hyperglycemia failed to increase the expression of cTnI when GATA-4 was silenced by small interfering RNA (siRNA) in H9c2 cells. Otherwise, activation of ERK is known to be a signal for phosphorylation of serine105 in GATA-4 to increase the DNA binding ability of this transcription factor. Moreover, GSK3β could directly interact with GATA-4 to cause GATA-4 to be exported from the nucleus. GATA-4 nuclear translocation and GSK3β ser9 phosphorylation were both elevated by a high glucose concentration in H9c2 cells. These changes were reversed by tiron (ROS scavenger), PD98059 (MEK/ERK inhibitor), or siRNA of GATA-4. Cell contractility measurement also indicated that the high glucose concentration decreased the contractility of H9c2 cells, and this was reduced by siRNA of GATA-4. Conclusions Hyperglycemia can cause systolic dysfunction and a higher expression of cTnI in cardiomyocytes through ROS, enhancing MEK/ERK-induced GATA-4 phosphorylation and accumulation in the cell nucleus.
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Affiliation(s)
- Po-Ming Ku
- Department of Medical Research, Chi-Mei Medical Center, No, 901 Chon-Hwa Road, Yong Kang, Tainan City, Taiwan
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Pound KM, Arteaga GM, Fasano M, Wilder T, Fischer SK, Warren CM, Wende AR, Farjah M, Abel ED, Solaro RJ, Lewandowski ED. Expression of slow skeletal TnI in adult mouse hearts confers metabolic protection to ischemia. J Mol Cell Cardiol 2011; 51:236-43. [PMID: 21640727 DOI: 10.1016/j.yjmcc.2011.05.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 04/26/2011] [Accepted: 05/14/2011] [Indexed: 12/30/2022]
Abstract
Changes in metabolic and myofilament phenotypes coincide in developing hearts. Posttranslational modification of sarcomere proteins influences contractility, affecting the energetic cost of contraction. However, metabolic adaptations to sarcomeric phenotypes are not well understood, particularly during pathophysiological stress. This study explored metabolic adaptations to expression of the fetal, slow skeletal muscle troponin I (ssTnI). Hearts expressing ssTnI exhibited no significant ATP loss during 5 min of global ischemia, while non-transgenic littermates (NTG) showed continual ATP loss. At 7 min ischemia TG-ssTnI hearts retained 80±12% of ATP versus 49±6% in NTG (P<0.05). Hearts expressing ssTnI also had increased AMPK phosphorylation. The mechanism of ATP preservation was augmented glycolysis. Glycolytic end products (lactate and alanine) were 38% higher in TG-ssTnI than NTG at 2 min and 27% higher at 5 min. This additional glycolysis was supported exclusively by exogenous glucose, and not glycogen. Thus, expression of a fetal myofilament protein in adult mouse hearts induced elevated anaerobic ATP production during ischemia via metabolic adaptations consistent with the resistance to hypoxia of fetal hearts. The general findings hold important relevance to both our current understanding of the association between metabolic and contractile phenotypes and the potential for invoking cardioprotective mechanisms against ischemic stress. This article is part of a Special Issue entitled "Possible Editorial".
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Affiliation(s)
- Kayla M Pound
- Program in Integrative Cardiac Metabolism, Center for Cardiovascular Research and Department of Physiology and Biophysics, University of Illinois at Chicago, College of Medicine, Chicago, IL 60612, USA
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Nan C, Huang X. Transcription factor Yin Yang 1 represses fetal troponin I gene expression in neonatal myocardial cells. Biochem Biophys Res Commun 2009; 378:62-7. [DOI: 10.1016/j.bbrc.2008.10.174] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Accepted: 10/30/2008] [Indexed: 10/21/2022]
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The vignette for V15 N5 issue. J Biomed Sci 2008. [DOI: 10.1007/s11373-008-9270-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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McWhinney C, Robishaw JD. Myocyte-specific M-CAT and MEF-1 elements regulate G-protein gamma 3 gene (gamma3) expression in cardiac myocytes. DNA Cell Biol 2008; 27:367-76. [PMID: 18613791 DOI: 10.1089/dna.2008.0754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Little is known regarding the mechanisms that control the expression of G-protein alpha, beta, and gamma subtypes. We have previously shown that the G-protein gamma(3) gene is expressed in the heart, brain, lung, spleen, kidney, muscle, and testis in mice. We have also reported that the G-protein gamma(3) subunit is expressed in rat cardiac myocytes, but not in cardiac fibroblasts. Other studies have shown that the gamma(3) subunit couples to the angiotensin A1A receptor in portal vein myocytes, and has been shown to mediate beta-adrenergic desensitization in cardiac myocytes treated with atorvastatin. In the present study, we evaluated G-protein gamma(3) promoter-luciferase reporter constructs in primary myocytes to identify key regulatory promoter regions. We identified two important regions of the promoter (upstream promoter region [UPR] and downstream promoter region [DPR]), which are required for expression in cardiac myocytes. We observed that removal of 48 bp in the UPR diminished gene transcription by 75%, and that the UPR contains consensus elements for myocyte-specific M-CAT and myocyte enhancer factor 1 (MEF-1) elements. The UPR and DPR share transcription factor elements for myocyte-specific M-CAT element. We observed that cardiac myocyte proteins bind to gamma(3) oligonucleotides containing transcription factor elements for myocyte-specific M-CAT and MEF-1. Myocyte-specific M-CAT proteins were supershifted with transcriptional enhancer factor-1 (TEF-1) antibodies binding to the gamma(3) M-CAT element, which is in agreement with reports showing that the M-CAT element binds the TEF-1 family of transcription factors. The 150 bp DPR contains three M-CAT elements, an INR element, an upstream stimulatory factor 1 element, and the transcription start site. We have shown that myocyte gamma(3) gene expression is regulated by myocyte-specific M-CAT and MEF-1 elements.
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Affiliation(s)
- Charlene McWhinney
- Biomedical Sciences Department, New York College of Osteopathic Medicine, Old Westbury, New York 11568-8000, USA.
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