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Wei C, Wang Z, Wang J, Teng J, Shen S, Xiao Q, Bao S, Feng Y, Zhang Y, Li Y, Sun S, Yue Y, Wu C, Wang Y, Zhou T, Xu W, Yu J, Wang L, Wang J. Conversion between 100-million-year-old duplicated genes contributes to rice subspecies divergence. BMC Genomics 2021; 22:460. [PMID: 34147070 PMCID: PMC8214281 DOI: 10.1186/s12864-021-07776-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/03/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Duplicated gene pairs produced by ancient polyploidy maintain high sequence similarity over a long period of time and may result from illegitimate recombination between homeologous chromosomes. The genomes of Asian cultivated rice Oryza sativa ssp. indica (XI) and Oryza sativa ssp. japonica (GJ) have recently been updated, providing new opportunities for investigating ongoing gene conversion events and their impact on genome evolution. RESULTS Using comparative genomics and phylogenetic analyses, we evaluated gene conversion rates between duplicated genes produced by polyploidization 100 million years ago (mya) in GJ and XI. At least 5.19-5.77% of genes duplicated across the three rice genomes were affected by whole-gene conversion after the divergence of GJ and XI at ~ 0.4 mya, with more (7.77-9.53%) showing conversion of only portions of genes. Independently converted duplicates surviving in the genomes of different subspecies often use the same donor genes. The ongoing gene conversion frequency was higher near chromosome termini, with a single pair of homoeologous chromosomes, 11 and 12, in each rice genome being most affected. Notably, ongoing gene conversion has maintained similarity between very ancient duplicates, provided opportunities for further gene conversion, and accelerated rice divergence. Chromosome rearrangements after polyploidization are associated with ongoing gene conversion events, and they directly restrict recombination and inhibit duplicated gene conversion between homeologous regions. Furthermore, we found that the converted genes tended to have more similar expression patterns than nonconverted duplicates. Gene conversion affects biological functions associated with multiple genes, such as catalytic activity, implying opportunities for interaction among members of large gene families, such as NBS-LRR disease-resistance genes, contributing to the occurrence of the gene conversion. CONCLUSION Duplicated genes in rice subspecies generated by grass polyploidization ~ 100 mya remain affected by gene conversion at high frequency, with important implications for the divergence of rice subspecies.
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Affiliation(s)
- Chendan Wei
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Zhenyi Wang
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Jianyu Wang
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Jia Teng
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Shaoqi Shen
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Qimeng Xiao
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Shoutong Bao
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Yishan Feng
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Yan Zhang
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Yuxian Li
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Sangrong Sun
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Yuanshuai Yue
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Chunyang Wu
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Yanli Wang
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Tianning Zhou
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Wenbo Xu
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China
| | - Jigao Yu
- University of Chinese Academy of Sciences, Beijing, 100049, China.,State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Science, Beijing, 100093, China
| | - Li Wang
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China.
| | - Jinpeng Wang
- School of Life Sciences, and Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000, Hebei, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Science, Beijing, 100093, China.
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Melo FV, Oliveira MM, Saibo NJM, Lourenço TF. Modulation of Abiotic Stress Responses in Rice by E3-Ubiquitin Ligases: A Promising Way to Develop Stress-Tolerant Crops. FRONTIERS IN PLANT SCIENCE 2021; 12:640193. [PMID: 33833769 PMCID: PMC8021960 DOI: 10.3389/fpls.2021.640193] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/17/2021] [Indexed: 05/25/2023]
Abstract
Plants are unable to physically escape environmental constraints and have, therefore, evolved a range of molecular and physiological mechanisms to maximize survival in an ever-changing environment. Among these, the post-translational modification of ubiquitination has emerged as an important mechanism to understand and improve the stress response. The ubiquitination of a given protein can change its abundance (through degradation), alter its localization, or even modulate its activity. Hence, ubiquitination increases the plasticity of the plant proteome in response to different environmental cues and can contribute to improve stress tolerance. Although ubiquitination is mediated by different enzymes, in this review, we focus on the importance of E3-ubiquitin ligases, which interact with the target proteins and are, therefore, highly associated with the mechanism specificity. We discuss their involvement in abiotic stress response and place them as putative candidates for ubiquitination-based development of stress-tolerant crops. This review covers recent developments in this field using rice as a reference for crops, highlighting the questions still unanswered.
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Liu C, Wang J, Sun P, Yu J, Meng F, Zhang Z, Guo H, Wei C, Li X, Shen S, Wang X. Illegitimate Recombination Between Homeologous Genes in Wheat Genome. FRONTIERS IN PLANT SCIENCE 2020; 11:1076. [PMID: 32849677 PMCID: PMC7396543 DOI: 10.3389/fpls.2020.01076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 06/30/2020] [Indexed: 05/30/2023]
Abstract
Polyploidies produce a large number of duplicated regions and genes in genomes, which have a long-term impact and stimulate genetic innovation. The high similarity between homeologous chromosomes, forming different subgenomes, or homologous regions after genome repatterning, may permit illegitimate DNA recombination. Here, based on gene colinearity, we aligned the (sub)genomes of common wheat (Triticum aestivum, AABBDD genotype) and its relatives, including Triticum urartu (AA), Aegilops tauschii (DD), and T. turgidum ssp. dicoccoides (AABB) to detect the homeologous (paralogous or orthologous) colinear genes within and between (sub)genomes. Besides, we inferred more ancient paralogous regions produced by a much ancient grass-common tetraploidization. By comparing the sequence similarity between paralogous and orthologous genes, we assumed abnormality in the topology of constructed gene trees, which could be explained by gene conversion as a result of illegitimate recombination. We found large numbers of inferred converted genes (>2,000 gene pairs) suggested long-lasting genome instability of the hexaploid plant, and preferential donor roles by DD genes. Though illegitimate recombination was much restricted, duplicated genes produced by an ancient whole-genome duplication, which occurred millions of years ago, also showed evidence of likely gene conversion. As to biological function, we found that ~40% catalytic genes in colinearity, including those involved in starch biosynthesis, were likely affected by gene conversion. The present study will contribute to understanding the functional and structural innovation of the common wheat genome.
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Affiliation(s)
- Chao Liu
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
| | - Jinpeng Wang
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
- National Key Laboratory for North China Crop Improvement and Regulation, Hebei Agriculture University, Baoding, China
| | - Pengchuan Sun
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
| | - Jigao Yu
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
| | - Fanbo Meng
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
- Institute for Genomics and Bio-Big-Data, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Zhikang Zhang
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
- Institute for Genomics and Bio-Big-Data, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - He Guo
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
| | - Chendan Wei
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
| | - Xinyu Li
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
| | - Shaoqi Shen
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
| | - Xiyin Wang
- School of Life Sciences, North China University of Science and Technology, Tangshan, China
- National Key Laboratory for North China Crop Improvement and Regulation, Hebei Agriculture University, Baoding, China
- Institute for Genomics and Bio-Big-Data, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Functional diversity of RING E3 ligases of major cereal crops in response to abiotic stresses. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s12892-017-0104-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Park YC, Kim JJ, Kim DS, Jang CS. Rice RING E3 ligase may negatively regulate gamma-ray response to mediate the degradation of photosynthesis-related proteins. PLANTA 2015; 241:1119-29. [PMID: 25600999 DOI: 10.1007/s00425-015-2242-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 01/04/2015] [Indexed: 05/24/2023]
Abstract
In this study, our findings regarding the regulation of GA irradiation-induced OsGIRP1 in relation to the levels of photosynthesis-related proteins such as OsrbcL1 and OsrbcS1 and hypersensitive responses of overexpressing plants to GR irradiation provide insight into the molecular functions of OsGIRP1 as a negative regulator in response to the stress of radiation. The RING (Really Interesting New Gene) finger proteins are known to play crucial roles in various abiotic stresses in plants. Here, we report on RING finger E3 ligase, Oryza sativa gamma rays-induced RING finger protein1 gene (OsGIRP1), which is highly induced by gamma rays (GR) irradiation. In vitro ubiquitination assay demonstrated that a single amino acid substitution (OsGIRP1(C196A)) of the RING domain showed no E3 ligase activity, supporting the notion that the activity of most E3s is specified by a RING domain. We isolated at least 6 substrate proteins of OsGIRP1, including 2 Rubisco subunits, OsrbcL1 and OsrbcSl, via yeast two-hybridization and bimolecular fluorescence complementation assays. OsGIRP1 and its partner proteins were targeted to the cytosol and the cytosol or chloroplasts, respectively; however, florescence signals of the complexes with OsGIPR1 were observed in the cytosol. Protein degradation in cell extracts showed that OsGIRP1 mediates proteolysis of 2 substrates, OsrbcS1 and OsrbcL1, via the 26S proteasome degradation pathway. The Arabidopsis plants overexpressing OsGIRP1 clearly exhibited increased sensitivity to GR irradiation. These results might suggest that OsGIRP1 acts as a negative regulator of GR response to mediate the degradation of photosynthesis-related proteins.
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Affiliation(s)
- Yong Chan Park
- Plant Genomics Lab, Department of Applied Plant Sciences, Kangwon National University, Chuncheon, 200-713, Republic of Korea
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Jung CG, Hwang SG, Park YC, Park HM, Kim DS, Park DH, Jang CS. Molecular characterization of the cold- and heat-induced Arabidopsis PXL1 gene and its potential role in transduction pathways under temperature fluctuations. JOURNAL OF PLANT PHYSIOLOGY 2015; 176:138-46. [PMID: 25602612 DOI: 10.1016/j.jplph.2015.01.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 01/01/2015] [Accepted: 01/01/2015] [Indexed: 05/26/2023]
Abstract
LRR-RLK (Leucine-Rich Repeat Receptor-Like Kinase) proteins are believed to play essential roles in cell-to-cell communication during various cellular processes including development, hormone perception, and abiotic stress responses. We isolated an LRR-RLK gene previously named Arabidopsis PHLOEM INTERCALATED WITH XYLEM-LIKE 1 (AtPXL1) and examined its expression patterns. AtPXL1 was highly induced by cold and heat stress, but not by drought. The fluorescence signal of 35S::AtPXL1-EGFP was closely localized to the plasma membrane. A yeast two-hybrid and bimolecular fluorescence complementation assay exhibited that AtPXL1 interacts with both proteins, A. thaliana histidine-rich dehydrin1 (AtHIRD1) and A. thaliana light-harvesting protein complex I (AtLHCA1). We found that AtPXL1 possesses autophosphorylation activity and phosphorylates AtHIRD1 and AtLHCA1 in an in vitro assay. Subsequently, we found that the knockout line (atpxl1) showed hypersensitive phenotypes when subjected to cold and heat during the germination stage, while the AtPXL1 overexpressing line as well as wild type plants showed high germination rates compared to the knockout plants. These results provide an insight into the molecular function of AtPXL1 in the regulation of signal transduction pathways under temperature fluctuations.
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Affiliation(s)
- Chang Gyo Jung
- Plant Genomics Laboratory, Department of Applied Plant Sciences, Kangwon National University, Chuncheon 200-713, Republic of Korea
| | - Sun-Goo Hwang
- Plant Genomics Laboratory, Department of Applied Plant Sciences, Kangwon National University, Chuncheon 200-713, Republic of Korea
| | - Yong Chan Park
- Plant Genomics Laboratory, Department of Applied Plant Sciences, Kangwon National University, Chuncheon 200-713, Republic of Korea
| | - Hyeon Mi Park
- Plant Genomics Laboratory, Department of Applied Plant Sciences, Kangwon National University, Chuncheon 200-713, Republic of Korea
| | - Dong Sub Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 1266 Singjeong, Jeongeup 580-185, Jeonbuk, Republic of Korea
| | - Duck Hwan Park
- Department of Applied Biology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-713, Republic of Korea
| | - Cheol Seong Jang
- Plant Genomics Laboratory, Department of Applied Plant Sciences, Kangwon National University, Chuncheon 200-713, Republic of Korea.
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Dametto A, Buffon G, Dos Reis Blasi ÉA, Sperotto RA. Ubiquitination pathway as a target to develop abiotic stress tolerance in rice. PLANT SIGNALING & BEHAVIOR 2015; 10:e1057369. [PMID: 26236935 PMCID: PMC4883960 DOI: 10.1080/15592324.2015.1057369] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 05/18/2023]
Abstract
Abiotic stresses may result in significant losses in rice grain productivity. Protein regulation by the ubiquitin/proteasome system has been studied as a target mechanism to optimize adaptation and survival strategies of plants to different environmental stresses. This article aimed at highlighting recent discoveries about the roles ubiquitination may play in the exposure of rice plants to different abiotic stresses, enabling the development of modified plants tolerant to stress. Responses provided by the ubiquitination process include the regulation of the stomatal opening, phytohormones levels, protein stabilization, cell membrane integrity, meristematic cell maintenance, as well as the regulation of reactive oxygen species and heavy metals levels. It is noticeable that ubiquitination is a potential means for developing abiotic stress tolerant plants, being an excellent alternative to rice (and other cultures) improvement programs.
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Affiliation(s)
- Andressa Dametto
- Programa de Pós-Graduação em Biotecnologia (PPGBiotec) and Centro Universitário UNIVATES; Lajeado, RS, Brazil
| | - Giseli Buffon
- Programa de Pós-Graduação em Biotecnologia (PPGBiotec) and Centro Universitário UNIVATES; Lajeado, RS, Brazil
| | | | - Raul Antonio Sperotto
- Programa de Pós-Graduação em Biotecnologia (PPGBiotec) and Centro Universitário UNIVATES; Lajeado, RS, Brazil
- Centro de Ciências Biológicas e da Saúde (CCBS); Centro Universitário UNIVATES; Lajeado, RS, Brazil
- Correspondence to: Raul Antonio Sperotto;
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Cho HY, Lee C, Hwang SG, Park YC, Lim HL, Jang CS. Overexpression of the OsChI1 gene, encoding a putative laccase precursor, increases tolerance to drought and salinity stress in transgenic Arabidopsis. Gene 2014; 552:98-105. [DOI: 10.1016/j.gene.2014.09.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 09/02/2014] [Accepted: 09/09/2014] [Indexed: 11/16/2022]
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Lim SD, Lee C, Jang CS. The rice RING E3 ligase, OsCTR1, inhibits trafficking to the chloroplasts of OsCP12 and OsRP1, and its overexpression confers drought tolerance in Arabidopsis. PLANT, CELL & ENVIRONMENT 2014; 37:1097-113. [PMID: 24215658 DOI: 10.1111/pce.12219] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 10/07/2013] [Accepted: 10/07/2013] [Indexed: 05/20/2023]
Abstract
Plant growth under low water availability adversely affects many key processes with morphological, physiological, biochemical and molecular consequences. Here, we found that a rice gene, OsCTR1, encoding the RING Ub E3 ligase plays an important role in drought tolerance. OsCTR1 was highly expressed in response to dehydration treatment and defense-related phytohormones, and its encoded protein was localized in both the chloroplasts and the cytosol. Intriguingly, the OsCTR1 protein was found predominantly targeted to the cytosol when rice protoplasts transfected with OsCTR1 were treated with abscisic acid (ABA). Several interacting partners were identified, which were mainly targeted to the chloroplasts, and interactions with OsCTR1 were confirmed by using biomolecular fluorescence complementation (BiFC). Interestingly, two chloroplast-localized proteins (OsCP12 and OsRP1) interacted with OsCTR1 in the cytosol, and ubiquitination by OsCTR1 led to protein degradation via the Ub 26S proteasome. Heterogeneous overexpression of OsCTR1 in Arabidopsis exhibited hypersensitive phenotypes with respect to ABA-responsive seed germination, seedling growth and stomatal closure. The ABA-sensitive transgenic plants also showed improvement in their tolerance against severe water deficits. Taken together, our findings lend support to the hypothesis that the molecular functions of OsCTR1 are related to tolerance to water-deficit stress via ABA-dependent regulation and related systems.
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Affiliation(s)
- Sung Don Lim
- Department of Applied Plant Sciences, Kangwon National University, Chuncheon, 200-713, Korea
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Molecular characterization of a heat inducible rice gene, OsHSP1, and implications for rice thermotolerance. Genes Genomics 2013. [DOI: 10.1007/s13258-013-0152-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cai J, Yang L, He HJ, Xu T, Liu HB, Wu Q, Ma Y, Liu QH, Nie MH. Antioxidant capacity responsible for a hypocholesterolemia is independent of dietary cholesterol in adult rats fed rice protein. Gene 2013; 533:57-66. [PMID: 24120393 DOI: 10.1016/j.gene.2013.09.124] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 09/29/2013] [Accepted: 09/30/2013] [Indexed: 01/02/2023]
Abstract
Dietary cholesterol and aging are major risk factors to accelerate oxidation process for developing hypercholesterolemia. The major aim of this study is to elucidate the effects of rice protein on cholesterol level and oxidative stress in adult rats fed with and without cholesterol. After 2 weeks of feeding, hepatic and plasma contents of cholesterol, reduced glutathione (GSH), oxidized glutathione (GSSG), malondialdehyde (MDA) and protein carbonyl (PCO) were measured. In liver, total antioxidative capacity (T-AOC), activities of antioxidant enzymes (total superoxide dismutase, T-SOD; catalase, CAT), glutathione metabolizing enzyme activities and gene expression levels (γ-glutamylcysteine synthetase, γ-GCS; glutathione reductase, GR; glutathione peroxidase, GPx) were determined. Under cholesterol-free/enriched dietary condition, T-AOC, activities of T-SOD and CAT, glutathione metabolism related enzymes' activities and mRNA levels (γ-GCS, GR and GPx) were effectively stimulated by rice proteins as compared to caseins. Compared with caseins, rice proteins significantly increased hepatic and plasma GSH contents, whereas hepatic and plasma accumulations of MDA, PCO and GSSG were significantly reduced by rice protein-feedings. As a result, the marked reductions of cholesterol in the plasma and in the liver were observed in adult rats fed rice proteins with and without cholesterol. The present study demonstrates that the hypocholesterolemic effect of rice protein is attributable to inducing antioxidative response and depressing oxidative damage in adult rats fed cholesterol-free/enriched diets. Results suggest that the antioxidant capability involved in the hypocholesterolemic action exerted by rice protein is independent of dietary cholesterol during adult period.
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Affiliation(s)
- Jixiang Cai
- Department of Food Science, School of Food Science and Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China
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Yang L, Chen JH, Xu T, Nie MH, Yang HK. Hypocholesterolemic effect of rice protein is due to regulating hepatic cholesterol metabolism in adult rats. Gene 2013; 512:470-6. [PMID: 23107769 DOI: 10.1016/j.gene.2012.10.042] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 10/11/2012] [Indexed: 01/04/2023]
Abstract
Aging is one of major risk factors for developing hypercholesterolemia. To elucidate the cholesterol-lowering mechanism exerted by rice protein (RP), the effects on hepatic cholesterol outputs and cholesterol metabolism related enzymes were investigated in adult rats, which were fed by casein (CAS) and RP without cholesterol in diets. After 2 weeks of feeding, the significant cholesterol-lowering effect was observed in adult rats fed by RP compared to CAS. The hepatic total- and VLDL-cholesterol secretions into circulation were significantly depressed in RP group, whereas biliary outputs of bile acids and cholesterol were effectively stimulated by RP-feeding, causing an increase in fecal sterol excretion compared to CAS. As a result, the apparent cholesterol absorption was significantly inhibited by RP. RP-feeding significantly increased the activity and gene expression of cholesterol 7α-hydroxylase, whereas acyl-CoA:cholesterol acyltransferase-2 activity and gene expression were significantly decreased by RP as compared with CAS. Neither activity nor gene expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase of RP did differ from CAS in the liver. The present study demonstrates that rice protein can prevent hypercholesterolemia through modifying hepatic cholesterol metabolism under cholesterol-free dietary condition. The findings suggest that hypocholesterolemic action induced by rice protein is attributed in part to the inhibition of cholesterol absorption during the adult period.
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Affiliation(s)
- Lin Yang
- Department of Food Science, School of Food Science and Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China.
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