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Challa NL, Sarkar A, Kapettu S, Phanithi PB, Chakrabarti P, Parsa KVL, Misra P. TGS1/PIMT regulates pro-inflammatory macrophage mediated paracrine insulin resistance: Crosstalk between macrophages and skeletal muscle cells. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166878. [PMID: 37673359 DOI: 10.1016/j.bbadis.2023.166878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 09/08/2023]
Abstract
Macrophage-driven chronic low-grade inflammatory response is intimately associated with pathogenesis of insulin resistance and type 2 diabetes (T2D). However, the molecular basis for skewing of pro-inflammatory macrophage is still elusive. Here, we describe the mechanism and significance of TGS1/PIMT (PRIP-Interacting protein with Methyl Transferase domain) in regulating macrophage activation and polarization and its impact on the development of insulin resistance in skeletal muscle cells. We show altered expression of TGS1 in M1 polarized cultured macrophages, bone marrow-derived (BMDM) and adipose tissue macrophages. Moreover, in High Fat Diet (HFD)-fed mice enhanced TGS1 expression is predominantly localized to the nucleus of adipose tissue macrophages suggesting its potential functional role. Gain and loss of TGS1 expression in macrophage further established its role in the secretion of pro-inflammatory mediators. Mechanistically, TGS1 controls the transcription of numerous genes linked to inflammation by forming a complex with Histone Acetyl Transferase (HAT)-containing transcriptional co-activators CBP and p300. Functionally, TGS1 mediated macrophage inflammatory response induces the development of insulin resistance in skeletal muscle cells and adipocytes. Our findings thus demonstrate an unexpected contribution of TGS1 in the regulation of macrophage mediated inflammation and insulin resistance highlighting that TGS1 antagonism could be a promising therapeutic target for the management of inflammation and insulin resistance in T2D.
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Affiliation(s)
- Naga Lakshmi Challa
- Centre for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life sciences, University of Hyderabad Campus, Hyderabad 500046, Telangana, India; Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka, India; Registered as a PhD student with MAHE, Manipal, India
| | - Ankita Sarkar
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, West Bengal, India
| | - Satyamoorthy Kapettu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka, India
| | - Prakash Babu Phanithi
- Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Partha Chakrabarti
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, West Bengal, India.
| | - Kishore V L Parsa
- Centre for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life sciences, University of Hyderabad Campus, Hyderabad 500046, Telangana, India.
| | - Parimal Misra
- Centre for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life sciences, University of Hyderabad Campus, Hyderabad 500046, Telangana, India.
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Edwin RK, Acharya LP, Maity SK, Chakrabarti P, Tantia O, Joshi MB, Satyamoorthy K, Parsa KVL, Misra P. TGS1/PIMT knockdown reduces lipid accumulation in adipocytes, limits body weight gain and promotes insulin sensitivity in mice. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166896. [PMID: 37751782 DOI: 10.1016/j.bbadis.2023.166896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/16/2023] [Accepted: 09/20/2023] [Indexed: 09/28/2023]
Abstract
PRIP Interacting protein with Methyl Transferase domain (PIMT/TGS1) is an integral upstream coactivator in the peroxisome proliferator-activated receptor gamma (PPARγ) transcriptional apparatus. PPARγ activation alleviates insulin resistance but promotes weight gain. Herein, we show how PIMT regulates body weight while promoting insulin sensitivity in diet induced obese mice. In vitro, we observed enhanced PIMT levels during adipogenesis. Knockdown of PIMT in 3T3-L1 results in reduced lipid accumulation and alters PPARγ regulated gene expression. Intraperitoneal injection of shPIMT lentivirus in high fat diet (HFD)-fed mice caused reduced adipose tissue size and decreased expression of lipid markers. This was accompanied by significantly lower levels of inflammation, hypertrophy and hyperplasia in the different adipose depots (eWAT and iWAT). Notably, PIMT depletion limits body weight gain in HFD-fed mice along with improved impaired oral glucose clearance. It also enhanced insulin sensitivity revealed by assessment of important insulin resistance markers and increased adiponectin levels. In addition, reduced PIMT levels did not alter the serum free fatty acid and TNFα levels. Finally, the relevance of our studies to human obesity is suggested by our finding that PIMT was upregulated in adipose tissue of obese patients along with crucial fat marker genes. We speculate that PIMT may be a potential target in maintaining energy metabolism, thus regulating obesity.
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Affiliation(s)
- Rebecca Kristina Edwin
- Centre for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500046, India; Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka 576104, India
| | - Lavanya Prakash Acharya
- Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka 576104, India
| | - Sujay K Maity
- Indian Institute of Chemical Biology (CSIR-IICB), 4, Raja Subodh Chandra Mallick Rd, Poddar Nagar, Jadavpur, Kolkata, West Bengal 700032, India
| | - Partha Chakrabarti
- Indian Institute of Chemical Biology (CSIR-IICB), 4, Raja Subodh Chandra Mallick Rd, Poddar Nagar, Jadavpur, Kolkata, West Bengal 700032, India
| | - Om Tantia
- Institute of Laparoscopic Surgery Group of Hospitals, DD - 6, Sector I, Salt Lake City, Kolkata 700064, West Bengal, India
| | - Manjunath B Joshi
- Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka 576104, India
| | - Kapaettu Satyamoorthy
- Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka 576104, India; SDM College of Medical Sciences and Hospital, Shri Dharmasthala Manjunatheshwara (SDM) University, Manjushree Nagar, Sattur, Dharwad, Karnataka 580009, India.
| | - Kishore V L Parsa
- Centre for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500046, India.
| | - Parimal Misra
- Centre for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500046, India.
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Talukdar PD, Chatterji U. Transcriptional co-activators: emerging roles in signaling pathways and potential therapeutic targets for diseases. Signal Transduct Target Ther 2023; 8:427. [PMID: 37953273 PMCID: PMC10641101 DOI: 10.1038/s41392-023-01651-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/27/2023] [Accepted: 09/10/2023] [Indexed: 11/14/2023] Open
Abstract
Specific cell states in metazoans are established by the symphony of gene expression programs that necessitate intricate synergic interactions between transcription factors and the co-activators. Deregulation of these regulatory molecules is associated with cell state transitions, which in turn is accountable for diverse maladies, including developmental disorders, metabolic disorders, and most significantly, cancer. A decade back most transcription factors, the key enablers of disease development, were historically viewed as 'undruggable'; however, in the intervening years, a wealth of literature validated that they can be targeted indirectly through transcriptional co-activators, their confederates in various physiological and molecular processes. These co-activators, along with transcription factors, have the ability to initiate and modulate transcription of diverse genes necessary for normal physiological functions, whereby, deregulation of such interactions may foster tissue-specific disease phenotype. Hence, it is essential to analyze how these co-activators modulate specific multilateral processes in coordination with other factors. The proposed review attempts to elaborate an in-depth account of the transcription co-activators, their involvement in transcription regulation, and context-specific contributions to pathophysiological conditions. This review also addresses an issue that has not been dealt with in a comprehensive manner and hopes to direct attention towards future research that will encompass patient-friendly therapeutic strategies, where drugs targeting co-activators will have enhanced benefits and reduced side effects. Additional insights into currently available therapeutic interventions and the associated constraints will eventually reveal multitudes of advanced therapeutic targets aiming for disease amelioration and good patient prognosis.
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Affiliation(s)
- Priyanka Dey Talukdar
- Cancer Research Laboratory, Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, West Bengal, India
| | - Urmi Chatterji
- Cancer Research Laboratory, Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, West Bengal, India.
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Sharma R, Maity SK, Chakrabarti P, Katika MR, Kapettu S, Parsa KVL, Misra P. PIMT Controls Insulin Synthesis and Secretion through PDX1. Int J Mol Sci 2023; 24:ijms24098084. [PMID: 37175791 PMCID: PMC10179560 DOI: 10.3390/ijms24098084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/28/2023] [Accepted: 04/05/2023] [Indexed: 05/15/2023] Open
Abstract
Pancreatic beta cell function is an important component of glucose homeostasis. Here, we investigated the function of PIMT (PRIP-interacting protein with methyl transferase domain), a transcriptional co-activator binding protein, in the pancreatic beta cells. We observed that the protein levels of PIMT, along with key beta cell markers such as PDX1 (pancreatic and duodenal homeobox 1) and MafA (MAF bZIP transcription factor A), were reduced in the beta cells exposed to hyperglycemic and hyperlipidemic conditions. Consistently, PIMT levels were reduced in the pancreatic islets isolated from high fat diet (HFD)-fed mice. The RNA sequencing analysis of PIMT knockdown beta cells identified that the expression of key genes involved in insulin secretory pathway, Ins1 (insulin 1), Ins2 (insulin 2), Kcnj11 (potassium inwardly-rectifying channel, subfamily J, member 11), Kcnn1 (potassium calcium-activated channel subfamily N member 1), Rab3a (member RAS oncogene family), Gnas (GNAS complex locus), Syt13 (synaptotagmin 13), Pax6 (paired box 6), Klf11 (Kruppel-Like Factor 11), and Nr4a1 (nuclear receptor subfamily 4, group A, member 1) was attenuated due to PIMT depletion. PIMT ablation in the pancreatic beta cells and in the rat pancreatic islets led to decreased protein levels of PDX1 and MafA, resulting in the reduction in glucose-stimulated insulin secretion (GSIS). The results from the immunoprecipitation and ChIP experiments revealed the interaction of PIMT with PDX1 and MafA, and its recruitment to the insulin promoter, respectively. Importantly, PIMT ablation in beta cells resulted in the nuclear translocation of insulin. Surprisingly, forced expression of PIMT in beta cells abrogated GSIS, while Ins1 and Ins2 transcript levels were subtly enhanced. On the other hand, the expression of genes, PRIP/Asc2/Ncoa6 (nuclear receptor coactivator 6), Pax6, Kcnj11, Syt13, Stxbp1 (syntaxin binding protein 1), and Snap25 (synaptosome associated protein 25) associated with insulin secretion, was significantly reduced, providing an explanation for the decreased GSIS upon PIMT overexpression. Our findings highlight the importance of PIMT in the regulation of insulin synthesis and secretion in beta cells.
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Affiliation(s)
- Rahul Sharma
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences (DRILS), University of Hyderabad Campus, Hyderabad 500046, India
| | - Sujay K Maity
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Partha Chakrabarti
- Division of Cell Biology and Physiology, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Madhumohan R Katika
- Central Research Lab Mobile Virology Research & Diagnostics BSL3 Lab, ESIC Medical College and Hospital, Hyderabad 500038, India
| | - Satyamoorthy Kapettu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education (MAHE), Manipal 576104, India
| | - Kishore V L Parsa
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences (DRILS), University of Hyderabad Campus, Hyderabad 500046, India
| | - Parimal Misra
- Center for Innovation in Molecular and Pharmaceutical Sciences (CIMPS), Dr. Reddy's Institute of Life Sciences (DRILS), University of Hyderabad Campus, Hyderabad 500046, India
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Kapadia B, Behera S, Kumar ST, Shah T, Edwin RK, Babu PP, Chakrabarti P, Parsa KV, Misra P. PIMT regulates hepatic gluconeogenesis in mice. iScience 2023; 26:106120. [PMID: 36866247 PMCID: PMC9972567 DOI: 10.1016/j.isci.2023.106120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 11/29/2022] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
The physiological and metabolic functions of PIMT/TGS1, a third-generation transcriptional apparatus protein, in glucose homeostasis sustenance are unclear. Here, we observed that the expression of PIMT was upregulated in the livers of short-term fasted and obese mice. Lentiviruses expressing Tgs1-specific shRNA or cDNA were injected into wild-type mice. Gene expression, hepatic glucose output, glucose tolerance, and insulin sensitivity were evaluated in mice and primary hepatocytes. Genetic modulation of PIMT exerted a direct positive impact on the gluconeogenic gene expression program and hepatic glucose output. Molecular studies utilizing cultured cells, in vivo models, genetic manipulation, and PKA pharmacological inhibition establish that PKA regulates PIMT at post-transcriptional/translational and post-translational levels. PKA enhanced 3'UTR-mediated translation of TGS1 mRNA and phosphorylated PIMT at Ser656, increasing Ep300-mediated gluconeogenic transcriptional activity. The PKA-PIMT-Ep300 signaling module and associated PIMT regulation may serve as a key driver of gluconeogenesis, positioning PIMT as a critical hepatic glucose sensor.
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Affiliation(s)
- Bandish Kapadia
- Center for Innovation in Molecular and Pharmaceutical Sciences, Dr. Reddy’s Institute of Life Sciences (DRILS), University of Hyderabad Campus, Hyderabad, TG 500046, India
| | - Soma Behera
- Center for Innovation in Molecular and Pharmaceutical Sciences, Dr. Reddy’s Institute of Life Sciences (DRILS), University of Hyderabad Campus, Hyderabad, TG 500046, India
| | - Sireesh T. Kumar
- Department of Biotechnology, University of Hyderabad, Hyderabad 500046, India
| | - Tapan Shah
- Department of Biochemistry, Saurashtra University, Rajkot 360005, India
| | - Rebecca Kristina Edwin
- Center for Innovation in Molecular and Pharmaceutical Sciences, Dr. Reddy’s Institute of Life Sciences (DRILS), University of Hyderabad Campus, Hyderabad, TG 500046, India
| | | | | | - Kishore V.L. Parsa
- Center for Innovation in Molecular and Pharmaceutical Sciences, Dr. Reddy’s Institute of Life Sciences (DRILS), University of Hyderabad Campus, Hyderabad, TG 500046, India,Corresponding author
| | - Parimal Misra
- Center for Innovation in Molecular and Pharmaceutical Sciences, Dr. Reddy’s Institute of Life Sciences (DRILS), University of Hyderabad Campus, Hyderabad, TG 500046, India,Corresponding author
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6
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Kayastha F, Herrington NB, Kapadia B, Roychowdhury A, Nanaji N, Kellogg GE, Gartenhaus RB. Novel eIF4A1 inhibitors with anti-tumor activity in lymphoma. Mol Med 2022; 28:101. [PMID: 36058921 PMCID: PMC9441068 DOI: 10.1186/s10020-022-00534-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/25/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Deregulated translation initiation is implicated extensively in cancer initiation and progression. It is actively pursued as a viable target that circumvents the dependency on oncogenic signaling, a significant factor in current strategies. Eukaryotic translation initiation factor (eIF) 4A plays an essential role in translation initiation by unwinding the secondary structure of messenger RNA (mRNA) upstream of the start codon, enabling active ribosomal recruitment on the downstream genes. Several natural product molecules with similar scaffolds, such as Rocaglamide A (RocA), targeting eIF4A have been reported in the last decade. However, their clinical utilization is still elusive due to several pharmacological limitations. In this study we identified new eIF4A1 inhibitors and their possible mechanisms. METHODS In this report, we conducted a pharmacophore-based virtual screen of RocA complexed with eIF4A and a polypurine RNA strand for novel eIF4A inhibitors from commercially available compounds in the MolPort Database. We performed target-based screening and optimization of active pharmacophores. We assessed the effects of novel compounds on biochemical and cell-based assays for efficacy and mechanistic evaluation. RESULTS We validated three new potent eIF4A inhibitors, RBF197, RBF 203, and RBF 208, which decreased diffuse large B-cell lymphoma (DLBCL) cell viability. Biochemical and cellular studies, molecular docking, and functional assays revealed that thosenovel compounds clamp eIF4A into mRNA in an ATP-independent manner. Moreover, we found that RBF197 and RBF208 significantly depressed eIF4A-dependent oncogene expression as well as the colony formation capacity of DLBCL. Interestingly, exposure of these compounds to non-malignant cells had only minimal impact on their growth and viability. CONCLUSIONS Identified compounds suggest a new strategy for designing novel eIF4A inhibitors.
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Affiliation(s)
- Forum Kayastha
- McGuire Cancer Center, Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA
- Division of Hematology, Oncology, and Palliative care, Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Noah B Herrington
- Department of Medicinal Chemistry, Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University School of Pharmacy, Richmond, VA, USA
| | - Bandish Kapadia
- McGuire Cancer Center, Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA
- Division of Hematology, Oncology, and Palliative care, Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Anirban Roychowdhury
- McGuire Cancer Center, Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA
- Division of Hematology, Oncology, and Palliative care, Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Nahid Nanaji
- Department of Veteran Affairs, Maryland Healthcare System, Baltimore, MD, USA
| | - Glen E Kellogg
- Department of Medicinal Chemistry, Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University School of Pharmacy, Richmond, VA, USA
| | - Ronald B Gartenhaus
- McGuire Cancer Center, Hunter Holmes McGuire VA Medical Center, Richmond, VA, USA.
- Division of Hematology, Oncology, and Palliative care, Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, USA.
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PIMT/TGS1: an evolving metabolic molecular switch with conserved methyl transferase activity. Drug Discov Today 2022; 27:2386-2393. [DOI: 10.1016/j.drudis.2022.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 03/01/2022] [Accepted: 04/14/2022] [Indexed: 11/18/2022]
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Trimethylguanosine synthase 1 is a novel regulator of pancreatic beta-cell mass and function. J Biol Chem 2022; 298:101592. [PMID: 35041827 PMCID: PMC8861161 DOI: 10.1016/j.jbc.2022.101592] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/06/2022] [Accepted: 01/08/2022] [Indexed: 01/23/2023] Open
Abstract
Type 2 diabetes is a metabolic disorder associated with abnormal glucose homeostasis and is characterized by intrinsic defects in β-cell function and mass. Trimethylguanosine synthase 1 (TGS1) is an evolutionarily conserved enzyme that methylates small nuclear and nucleolar RNAs and that is involved in pre-mRNA splicing, transcription, and ribosome production. However, the role of TGS1 in β-cells and glucose homeostasis had not been explored. Here, we show that TGS1 is upregulated by insulin and upregulated in islets of Langerhans from mice exposed to a high-fat diet and in human β-cells from type 2 diabetes donors. Using mice with conditional (βTGS1KO) and inducible (MIP-CreERT-TGS1KO) TGS1 deletion, we determined that TGS1 regulates β-cell mass and function. Using unbiased approaches, we identified a link between TGS1 and endoplasmic reticulum stress and cell cycle arrest, as well as and how TGS1 regulates β-cell apoptosis. We also found that deletion of TGS1 results in an increase in the unfolded protein response by increasing XBP-1, ATF-4, and the phosphorylation of eIF2α, in addition to promoting several changes in cell cycle inhibitors and activators such as p27 and Cyclin D2. This study establishes TGS1 as a key player regulating β-cell mass and function. We propose that these observations can be used as a stepping-stone for the design of novel strategies focused on TGS1 as a therapeutic target for the treatment of diabetes.
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Colono C, Ortiz JPA, Permingeat HR, Souza Canada ED, Siena LA, Spoto N, Galdeano F, Espinoza F, Leblanc O, Pessino SC. A Plant-Specific TGS1 Homolog Influences Gametophyte Development in Sexual Tetraploid Paspalum notatum Ovules. FRONTIERS IN PLANT SCIENCE 2019; 10:1566. [PMID: 31850040 PMCID: PMC6895069 DOI: 10.3389/fpls.2019.01566] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 11/08/2019] [Indexed: 05/04/2023]
Abstract
Aposporous apomictic plants form clonal maternal seeds by inducing the emergence of non-reduced (2n) embryo sacs in the ovule nucellus and the development of embryos by parthenogenesis. In previous work, we reported a plant-specific TRIMETHYLGUANOSINE SYNTHASE 1 (TGS1) gene (PN_TGS1-like) showing expression levels positively correlated with sexuality rates in facultative apomictic Paspalum notatum. PN_ TGS1-like displayed contrasting in situ hybridization patterns in apomictic and sexual plant ovules from premeiosis to anthesis. Here we transformed sexual P. notatum with a TGS1-like antisense construction under a constitutive promoter, in order to produce lines with reduced transcript representation. Antisense plants developed prominent trichomes on the adaxial leaf surface, a trait absent from control genotypes. Reproductive development analysis revealed occasional formation of twin ovules. While control individuals typically displayed a single meiotic embryo sac per ovule, antisense lines showed 12.93-15.79% of ovules bearing extra nuclei, which can be assigned to aposporous-like embryo sacs (AES-like) or, alternatively, to gametophytes with a misguided cell fate development. Moreover, around 8.42-9.52% of ovules showed what looked like a combination of meiotic and aposporous-like sacs. Besides, 32.5% of ovules at early developmental stages displayed nucellar cells with prominent nuclei resembling apospory initials (AIs), which surrounded the megaspore mother cell (MMC) or the MMC-derived meiotic products. Two or more concurrent meiosis events were never detected, which suggest a non-reduced nature for the extra nuclei observed in the mature ovules, unless they were generated by proliferation and misguided differentiation of the legitimate meiotic products. The antisense lines produced a similar amount of viable even-sized pollen with respect to control genotypes, and formed an equivalent full seed set (∼9% of total seeds) after self-pollination. Flow cytometry analyses of caryopses derived from antisense lines revealed that all full seeds had originated from meiotic embryo sacs (i.e. by sexuality). A reduction of 25.55% in the germination percentage was detected when comparing antisense lines with controls. Our results indicate that PN_ TGS1-like influences ovule, gametophyte and possibly embryo development.
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Affiliation(s)
- Carolina Colono
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Juan Pablo A. Ortiz
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Hugo R. Permingeat
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | | | - Lorena A. Siena
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Nicolás Spoto
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Florencia Galdeano
- Genetics Laboratory, IBONE, CONICET, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Francisco Espinoza
- Genetics Laboratory, IBONE, CONICET, Universidad Nacional del Nordeste, Corrientes, Argentina
| | | | - Silvina C. Pessino
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
- *Correspondence: Silvina C. Pessino,
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Mancini M, Permingeat H, Colono C, Siena L, Pupilli F, Azzaro C, de Alencar Dusi DM, de Campos Carneiro VT, Podio M, Seijo JG, González AM, Felitti SA, Ortiz JPA, Leblanc O, Pessino SC. The MAP3K-Coding QUI-GON JINN ( QGJ) Gene Is Essential to the Formation of Unreduced Embryo Sacs in Paspalum. FRONTIERS IN PLANT SCIENCE 2018; 9:1547. [PMID: 30405677 PMCID: PMC6207905 DOI: 10.3389/fpls.2018.01547] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/03/2018] [Indexed: 05/20/2023]
Abstract
Apomixis is a clonal mode of reproduction via seeds, which results from the failure of meiosis and fertilization in the sexual female reproductive pathway. In previous transcriptomic surveys, we identified a mitogen-activated protein kinase kinase kinase (N46) displaying differential representation in florets of sexual and apomictic Paspalum notatum genotypes. Here, we retrieved and characterized the N46 full cDNA sequence from sexual and apomictic floral transcriptomes. Phylogenetic analyses showed that N46 was a member of the YODA family, which was re-named QUI-GON JINN (QGJ). Differential expression in florets of sexual and apomictic plants was confirmed by qPCR. In situ hybridization experiments revealed expression in the nucellus of aposporous plants' ovules, which was absent in sexual plants. RNAi inhibition of QGJ expression in two apomictic genotypes resulted in significantly reduced rates of aposporous embryo sac formation, with respect to the level detected in wild type aposporous plants and transformation controls. The QGJ locus segregated independently of apospory. However, a probe derived from a related long non-coding RNA sequence (PN_LNC_QGJ) revealed RFLP bands cosegregating with the Paspalum apospory-controlling region (ACR). PN_LNC_QGJ is expressed in florets of apomictic plants only. Our results indicate that the activity of QGJ in the nucellus of apomictic plants is necessary to form non-reduced embryo sacs and that a long non-coding sequence with regulatory potential is similar to sequences located within the ACR.
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Affiliation(s)
- Micaela Mancini
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Hugo Permingeat
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Carolina Colono
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Lorena Siena
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Fulvio Pupilli
- Istituto di Bioscienze e BioRisorse, Consiglio Nazionale delle Ricerche, Perugia, Italy
| | - Celeste Azzaro
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | | | | | - Maricel Podio
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - José Guillermo Seijo
- Instituto de Botánica del Nordeste, CONICET-UNNE, Corrientes, Argentina
- Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Ana María González
- Instituto de Botánica del Nordeste, CONICET-UNNE, Corrientes, Argentina
- Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Silvina A. Felitti
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Juan Pablo A. Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | | | - Silvina C. Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
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11
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2-[2-(4-(trifluoromethyl)phenylamino)thiazol-4-yl]acetic acid (Activator-3) is a potent activator of AMPK. Sci Rep 2018; 8:9599. [PMID: 29942003 PMCID: PMC6018554 DOI: 10.1038/s41598-018-27974-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 06/06/2018] [Indexed: 02/08/2023] Open
Abstract
AMPK is considered as a potential high value target for metabolic disorders. Here, we present the molecular modeling, in vitro and in vivo characterization of Activator-3, 2-[2-(4-(trifluoromethyl)phenylamino)thiazol-4-yl]acetic acid, an AMP mimetic and a potent pan-AMPK activator. Activator-3 and AMP likely share common activation mode for AMPK activation. Activator-3 enhanced AMPK phosphorylation by upstream kinase LKB1 and protected AMPK complex against dephosphorylation by PP2C. Molecular modeling analyses followed by in vitro mutant AMPK enzyme assays demonstrate that Activator-3 interacts with R70 and R152 of the CBS1 domain on AMPK γ subunit near AMP binding site. Activator-3 and C2, a recently described AMPK mimetic, bind differently in the γ subunit of AMPK. Activator-3 unlike C2 does not show cooperativity of AMPK activity in the presence of physiological concentration of ATP (2 mM). Activator-3 displays good pharmacokinetic profile in rat blood plasma with minimal brain penetration property. Oral treatment of High Sucrose Diet (HSD) fed diabetic rats with 10 mg/kg dose of Activator-3 once in a day for 30 days significantly enhanced glucose utilization, improved lipid profiles and reduced body weight, demonstrating that Activator-3 is a potent AMPK activator that can alleviate the negative metabolic impact of high sucrose diet in rat model.
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12
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Behera S, Kapadia B, Kain V, Alamuru-Yellapragada NP, Murunikkara V, Kumar ST, Babu PP, Seshadri S, Shivarudraiah P, Hiriyan J, Gangula NR, Maddika S, Misra P, Parsa KV. ERK1/2 activated PHLPP1 induces skeletal muscle ER stress through the inhibition of a novel substrate AMPK. Biochim Biophys Acta Mol Basis Dis 2018; 1864:1702-1716. [DOI: 10.1016/j.bbadis.2018.02.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/29/2018] [Accepted: 02/22/2018] [Indexed: 11/28/2022]
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13
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Alamuru-Yellapragada NP, Vundyala S, Behera S, Parsa KVL. LPS depletes PHLPP levels in macrophages through the inhibition of SP1 dependent transcriptional regulation. Biochem Biophys Res Commun 2017; 486:533-538. [PMID: 28322791 DOI: 10.1016/j.bbrc.2017.03.080] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 03/17/2017] [Indexed: 11/18/2022]
Abstract
We have previously reported that bacterial endotoxin LPS attenuates expression of PHLPP, a ser/thr phosphatase, at both transcript and protein levels in different immune cells, however the underlying molecular mechanism is unknown and is of significant interest. Here, in line with the decreased transcript levels upon LPS treatment, we observed that LPS caused significant reduction in PHLPP promoter activity. We observed that SP1, a transcription factor frequently associated with inflammation, was recruited to the PHLPP promoter region. Ectopic expression of SP1 enhanced both transcript and protein levels of PHLPP while knockdown of SP1 or pharmacological inhibition of SP1 DNA binding by mithramycin reduced PHLPP expression. Moreover, over-expression of SP1 co-activators CBP/p300 augmented SP1 driven PHLPP promoter activity. Of note, LPS treatment depleted SP1 and CBP protein levels due to which recruitment of SP1 to PHLPP promoter was reduced. Further, we found that re-introduction of SP1 restored promoter activity and transcript levels of PHLPP in LPS stimulated cells. Collectively, our data revealed the molecular mechanism underlying the regulation of PHLPP expression during LPS induced macrophage inflammatory response.
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Affiliation(s)
- Neeraja P Alamuru-Yellapragada
- Department of Biology, Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, Telangana, India
| | - Sanghamitra Vundyala
- Department of Biology, Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, Telangana, India
| | - Soma Behera
- Department of Biology, Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, Telangana, India
| | - Kishore V L Parsa
- Department of Biology, Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, Telangana, India.
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14
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Taddeo EP, Hargett SR, Lahiri S, Nelson ME, Liao JA, Li C, Slack-Davis JK, Tomsig JL, Lynch KR, Yan Z, Harris TE, Hoehn KL. Lysophosphatidic acid counteracts glucagon-induced hepatocyte glucose production via STAT3. Sci Rep 2017; 7:127. [PMID: 28273928 PMCID: PMC5428006 DOI: 10.1038/s41598-017-00210-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/14/2017] [Indexed: 01/25/2023] Open
Abstract
Hepatic glucose production (HGP) is required to maintain normoglycemia during fasting. Glucagon is the primary hormone responsible for increasing HGP; however, there are many additional hormone and metabolic factors that influence glucagon sensitivity. In this study we report that the bioactive lipid lysophosphatidic acid (LPA) regulates hepatocyte glucose production by antagonizing glucagon-induced expression of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK). Treatment of primary hepatocytes with exogenous LPA blunted glucagon-induced PEPCK expression and glucose production. Similarly, knockout mice lacking the LPA-degrading enzyme phospholipid phosphate phosphatase type 1 (PLPP1) had a 2-fold increase in endogenous LPA levels, reduced PEPCK levels during fasting, and decreased hepatic gluconeogenesis in response to a pyruvate challenge. Mechanistically, LPA antagonized glucagon-mediated inhibition of STAT3, a transcriptional repressor of PEPCK. Importantly, LPA did not blunt glucagon-stimulated glucose production or PEPCK expression in hepatocytes lacking STAT3. These data identify a novel role for PLPP1 activity and hepatocyte LPA levels in glucagon sensitivity via a mechanism involving STAT3.
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Affiliation(s)
- Evan P Taddeo
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Stefan R Hargett
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Sujoy Lahiri
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Marin E Nelson
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Jason A Liao
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Chien Li
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Jill K Slack-Davis
- Department of Microbiology, Immunology and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Jose L Tomsig
- Department of Toxicology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Kevin R Lynch
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Zhen Yan
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA.,Robert M. Berne Cardiovascular Research Center, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Thurl E Harris
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Kyle L Hoehn
- Department of Pharmacology, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA. .,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, Sydney, NSW, 2052, Australia.
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15
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Co-activator binding protein PIMT mediates TNF-α induced insulin resistance in skeletal muscle via the transcriptional down-regulation of MEF2A and GLUT4. Sci Rep 2015; 5:15197. [PMID: 26468734 PMCID: PMC4606566 DOI: 10.1038/srep15197] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/21/2015] [Indexed: 12/18/2022] Open
Abstract
The mechanisms underlying inflammation induced insulin resistance are poorly understood. Here, we report that the expression of PIMT, a transcriptional co-activator binding protein, was up-regulated in the soleus muscle of high sucrose diet (HSD) induced insulin resistant rats and TNF-α exposed cultured myoblasts. Moreover, TNF-α induced phosphorylation of PIMT at the ERK1/2 target site Ser298. Wild type (WT) PIMT or phospho-mimic Ser298Asp mutant but not phospho-deficient Ser298Ala PIMT mutant abrogated insulin stimulated glucose uptake by L6 myotubes and neonatal rat skeletal myoblasts. Whereas, PIMT knock down relieved TNF-α inhibited insulin signaling. Mechanistic analysis revealed that PIMT differentially regulated the expression of GLUT4, MEF2A, PGC-1α and HDAC5 in cultured cells and skeletal muscle of Wistar rats. Further characterization showed that PIMT was recruited to GLUT4, MEF2A and HDAC5 promoters and overexpression of PIMT abolished the activity of WT but not MEF2A binding defective mutant GLUT4 promoter. Collectively, we conclude that PIMT mediates TNF-α induced insulin resistance at the skeletal muscle via the transcriptional modulation of GLUT4, MEF2A, PGC-1α and HDAC5 genes.
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16
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Kain V, Kapadia B, Misra P, Saxena U. Simvastatin may induce insulin resistance through a novel fatty acid mediated cholesterol independent mechanism. Sci Rep 2015; 5:13823. [PMID: 26345110 PMCID: PMC4561915 DOI: 10.1038/srep13823] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 08/06/2015] [Indexed: 11/30/2022] Open
Abstract
Statins are a class of oral drugs that are widely used for treatment of hypercholesterolemia. Recent clinical data suggest that chronic use of these drugs increases the frequency of new onset diabetes. Studies to define the risks of statin-induced diabetes and its underlying mechanisms are clearly necessary. We explored the possible mechanism of statin induced insulin resistance using a well-established cell based model and simvastatin as a prototype statin. Our data show that simvastatin induces insulin resistance in a cholesterol biosynthesis inhibition independent fashion but does so by a fatty acid mediated effect on insulin signaling pathway. These data may help design strategies for prevention of statin induced insulin resistance and diabetes in patients with hypercholesterolemia.
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Affiliation(s)
- Vasundhara Kain
- Department of Biology, Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, Telangana, India
| | - Bandish Kapadia
- Department of Biology, Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, Telangana, India
| | - Parimal Misra
- Department of Biology, Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, Telangana, India
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17
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Winiarska K, Jarzyna R, Dzik JM, Jagielski AK, Grabowski M, Nowosielska A, Focht D, Sierakowski B. ERK1/2 pathway is involved in renal gluconeogenesis inhibition under conditions of lowered NADPH oxidase activity. Free Radic Biol Med 2015; 81:13-21. [PMID: 25601753 DOI: 10.1016/j.freeradbiomed.2014.12.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/27/2014] [Accepted: 12/26/2014] [Indexed: 01/11/2023]
Abstract
The aim of this study was to elucidate the mechanisms involved in the inhibition of renal gluconeogenesis occurring under conditions of lowered activity of NADPH oxidase (Nox), the enzyme considered to be one of the main sources of reactive oxygen species in kidneys. The in vitro experiments were performed on primary cultures of rat renal proximal tubules, with the use of apocynin, a selective Nox inhibitor, and TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl), a potent superoxide radical scavenger. In the in vivo experiments, Zucker diabetic fatty (ZDF) rats, a well established model of diabetes type 2, were treated with apocynin solution in drinking water. The main in vitro findings are the following: (1) both apocynin and TEMPOL attenuate the rate of gluconeogenesis, inhibiting the step catalyzed by phosphoenolpyruvate carboxykinase (PEPCK), a key enzyme of the process; (2) in the presence of the above-noted compounds the expression of PEPCK and the phosphorylation of transcription factor CREB and ERK1/2 kinases are lowered; (3) both U0126 (MEK inhibitor) and 3-(2-aminoethyl)-5-((4-ethoxyphenyl)methylene)-2,4-thiazolidinedione (ERK inhibitor) diminish the rate of glucose synthesis via mechanisms similar to those of apocynin and TEMPOL. The observed apocynin in vivo effects include: (1) slight attenuation of hyperglycemia; (2) inhibition of renal gluconeogenesis; (3) a decrease in renal PEPCK activity and content. In view of the results summarized above, it can be concluded that: (1) the lowered activity of the ERK1/2 pathway is of importance for the inhibition of renal gluconeogenesis found under conditions of lowered superoxide radical production by Nox; (2) the mechanism of this phenomenon includes decreased PEPCK expression, resulting from diminished activity of transcription factor CREB; (3) apocynin-evoked inhibition of renal gluconeogenesis contributes to the hypoglycemic action of this compound observed in diabetic animals. Thus, the study has delivered some new insights into the recently discussed issue of the usefulness of Nox inhibition as a potential antidiabetic strategy.
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Affiliation(s)
- Katarzyna Winiarska
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland.
| | - Robert Jarzyna
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Jolanta M Dzik
- Department of Biochemistry, Faculty of Agriculture and Biology, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Adam K Jagielski
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Michal Grabowski
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Agata Nowosielska
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Dorota Focht
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Bartosz Sierakowski
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
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18
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Siena LA, Ortiz JPA, Leblanc O, Pessino S. PnTgs1-like expression during reproductive development supports a role for RNA methyltransferases in the aposporous pathway. BMC PLANT BIOLOGY 2014; 14:297. [PMID: 25404464 PMCID: PMC4243328 DOI: 10.1186/s12870-014-0297-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 10/20/2014] [Indexed: 05/19/2023]
Abstract
BACKGROUND In flowering plants, apomixis (asexual reproduction via seeds) is widely believed to result from failure of key regulators of the sexual female reproductive pathway. In the past few years, both differential display and RNA-seq comparative approaches involving reproductive organs of sexual plants and their apomictic counterparts have yielded extensive lists of candidate genes. Nevertheless, only a limited number of these genes have been functionally characterized, with few clues consequently available for understanding the molecular control of apomixis. We have previously identified several cDNA fragments with high similarity to genes involved in RNA biology and with differential amplification between sexual and apomictic Paspalum notatum plants. Here, we report the characterization of one of these candidates, namely, N69 encoding a protein of the S-adenosyl-L-methionine-dependent methyltransferases superfamily. The purpose of this work was to extend the N69 cDNA sequence and to characterize its expression at different developmental stages in both sexual and apomictic individuals. RESULTS Molecular characterization of the N69 cDNA revealed homology with genes encoding proteins similar to yeast and mammalian trimethylguanosine synthase/PRIP-interacting proteins. These proteins play a dual role as ERK2-controlled transcriptional coactivators and mediators of sn(o)RNA and telomerase RNA cap trimethylation, and participate in mammals and yeast development. The N69-extended sequence was consequently renamed PnTgs1-like. Expression of PnTgs1-like during reproductive development was significantly higher in floral organs of sexual genotypes compared with apomicts. This difference was not detected in vegetative tissues. In addition, expression levels in reproductive tissues of several genotypes were negatively correlated with facultative apomixis rates. Moreover, in situ hybridization observations revealed that PnTgs1-like expression is relatively higher in ovules of sexual plants throughout development, from premeiosis to maturity. Tissues where differential expression is detected include nucellar cells, the site of aposporous initials differentiation in apomictic genotypes. CONCLUSIONS Our results indicate that PnTgs1-like (formerly N69) encodes a trimethylguanosine synthase-like protein whose function in mammals and yeast is critical for development, including reproduction. Our findings also suggest a pivotal role for this candidate gene in nucellar cell fate, as its diminished expression is correlated with initiation of the apomictic pathway in plants.
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Affiliation(s)
- Lorena A Siena
- />Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Parque Villarino, (S2125ZAA) Zavalla, Santa Fe, Argentina
| | - Juan Pablo A Ortiz
- />Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Parque Villarino, (S2125ZAA) Zavalla, Santa Fe, Argentina
- />Instituto de Botánica del Nordeste -IBONE- (UNNE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Sargento Cabral 2131, 3400 Corrientes, Argentina
| | - Olivier Leblanc
- />Institut de Recherche pour le Développement, ERL 5300 IRD/CNRS, UMR 232 IRD/Université de Montpellier 2, 911 Avenue Agropolis, Montpellier, France
| | - Silvina Pessino
- />Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Parque Villarino, (S2125ZAA) Zavalla, Santa Fe, Argentina
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