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Jung H, Park HJ, Jo SH, Lee A, Lee HJ, Kim HS, Jung C, Cho HS. Nuclear OsFKBP20-1b maintains SR34 stability and promotes the splicing of retained introns upon ABA exposure in rice. New Phytol 2023; 238:2476-2494. [PMID: 36942934 DOI: 10.1111/nph.18892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/16/2023] [Indexed: 05/19/2023]
Abstract
Alternative splicing (AS) is a critical means by which plants respond to changes in the environment, but few splicing factors contributing to AS have been reported and functionally characterized in rice (Oryza sativa L.). Here, we explored the function and molecular mechanism of the spliceosome-associated protein OsFKBP20-1b during AS. We determined the AS landscape of wild-type and osfkbp20-1b knockout plants upon abscisic acid (ABA) treatment by transcriptome deep sequencing. To capture the dynamics of translating intron-containing mRNAs, we blocked transcription with cordycepin and performed polysome profiling. We also analyzed whether OsFKBP20-1b and the splicing factors OsSR34 and OsSR45 function together in AS using protoplast transfection assays. We show that OsFKBP20-1b interacts with OsSR34 and regulates its stability, suggesting a role as a chaperone-like protein in the spliceosome. OsFKBP20-1b facilitates the splicing of mRNAs with retained introns after ABA treatment; some of these mRNAs are translatable and encode functional transcriptional regulators of stress-responsive genes. In addition, interacting proteins, OsSR34 and OsSR45, regulate the splicing of the same retained introns as OsFKBP20-1b after ABA treatment. Our findings reveal that spliceosome-associated immunophilin functions in alternative RNA splicing in rice by positively regulating the splicing of retained introns to limit ABA response.
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Affiliation(s)
- Haemyeong Jung
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Hyun Ji Park
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
| | - Seung Hee Jo
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Areum Lee
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Hyo-Jun Lee
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Functional Genomics, KRIBB School of Bioscience, UST, Daejeon, 34113, South Korea
| | - Hyun-Soon Kim
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Choonkyun Jung
- Department of International Agricultural Technology and Crop Biotechnology Institute/Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, South Korea
- Department of Agriculture, Forestry, and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, South Korea
| | - Hye Sun Cho
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
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Barnes EK, Kwon M, Hodgins CL, Qu Y, Kim SW, Yeung EC, Ro DK. The promoter sequences of lettuce cis-prenyltransferase and its binding protein specify gene expression in laticifers. Planta 2021; 253:51. [PMID: 33507397 DOI: 10.1007/s00425-021-03566-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
MAIN CONCLUSION Promoters of lettuce cis-prenyltransferase 3 (LsCPT3) and CPT-binding protein 2 (LsCBP2) specify gene expression in laticifers, as supported by in situ β-glucuronidase stains and microsection analysis. Lettuce (Lactuca sativa) has articulated laticifers alongside vascular bundles. In the cytoplasm of laticifers, natural rubber (cis-1,4-polyisoprene) is synthesized by cis-prenyltransferase (LsCPT3) and CPT-binding protein (LsCBP2), both of which form an enzyme complex. Here we determined the gene structures of LsCPT3 and LsCBP2 and characterized their promoter activities using β-glucuronidase (GUS) reporter assays in stable transgenic lines of lettuce. LsCPT3 has a single 7.4-kb intron while LsCBP2 has seven introns including a 940-bp intron in the 5'-untranslated region (UTR). Serially truncated LsCPT3 promoters (2.3 kb, 1.6 kb, and 1.1 kb) and the LsCBP2 promoter with (1.7 kb) or without (0.8 kb) the 940-bp introns were fused to GUS to examine their promoter activities. In situ GUS stains of the transgenic plants revealed that the 1.1-kb LsCPT3 and 0.8-kb LsCBP2 promoter without the 5'-UTR intron are sufficient to express GUS exclusively in laticifers. Fluorometric assays showed that the LsCBP2 promoter was several-fold stronger than the CaMV35S promoter and was ~ 400 times stronger than the LsCPT3 promoter in latex. Histochemical analyses confirmed that both promoters express GUS exclusively in laticifers, recognized by characteristic fused multicellular structures. We concluded that both the LsCPT3 and LsCBP2 promoters specify gene expression in laticifers, and the LsCBP2 promoter displays stronger expression than the CaMV35S promoter in laticifers. For the LsCPT3 promoter, it appears that unknown cis-elements outside of the currently examined LsCPT3 promoter are required to enhance LsCPT3 expression.
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Affiliation(s)
- Elysabeth K Barnes
- Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Moonhyuk Kwon
- Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
- Division of Applied Life Sciences (BK21 Plus), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Connor L Hodgins
- Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Yang Qu
- Department of Chemistry, University of New Brunswick Fredericton, Fredericton, E3B 5A3, Canada
| | - Seon-Won Kim
- Division of Applied Life Sciences (BK21 Plus), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Edward C Yeung
- Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Dae-Kyun Ro
- Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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