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Takagi H, Lee N, Hempton AK, Purushwani S, Notaguchi M, Yamauchi K, Shirai K, Kawakatsu Y, Uehara S, Albers WG, Downing BLR, Ito S, Suzuki T, Matsuura T, Mori IC, Mitsuda N, Kurihara D, Matsushita T, Song YH, Sato Y, Nomoto M, Tada Y, Hanada K, Cuperus JT, Queitsch C, Imaizumi T. Florigen-producing cells express FPF1-LIKE PROTEIN 1 that accelerates flowering and stem growth in long days with sunlight red/far-red ratio in Arabidopsis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591289. [PMID: 38746097 PMCID: PMC11092471 DOI: 10.1101/2024.04.26.591289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Seasonal changes in spring induce flowering by expressing the florigen, FLOWERING LOCUS T (FT), in Arabidopsis. FT is expressed in unique phloem companion cells with unknown characteristics. The question of which genes are co-expressed with FT and whether they have roles in flowering remains elusive. Through tissue-specific translatome analysis, we discovered that under long-day conditions with the natural sunlight red/far-red ratio, the FT-producing cells express a gene encoding FPF1-LIKE PROTEIN 1 (FLP1). The master FT regulator, CONSTANS (CO), controls FLP1 expression, suggesting FLP1's involvement in the photoperiod pathway. FLP1 promotes early flowering independently of FT, is active in the shoot apical meristem, and induces the expression of SEPALLATA 3 (SEP3), a key E-class homeotic gene. Unlike FT, FLP1 facilitates inflorescence stem elongation. Our cumulative evidence indicates that FLP1 may act as a mobile signal. Thus, FLP1 orchestrates floral initiation together with FT and promotes inflorescence stem elongation during reproductive transitions.
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Affiliation(s)
- Hiroshi Takagi
- Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA
- Center for Gene Research, Nagoya University, Nagoya, 464-8602, Japan
| | - Nayoung Lee
- Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
| | - Andrew K. Hempton
- Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA
| | - Savita Purushwani
- Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA
| | - Michitaka Notaguchi
- Bioscience and Biotechnology Center, Nagoya University, Nagoya, 464-8601, Japan
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Kota Yamauchi
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, 820-8502, Japan
| | - Kazumasa Shirai
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, 820-8502, Japan
| | - Yaichi Kawakatsu
- Bioscience and Biotechnology Center, Nagoya University, Nagoya, 464-8601, Japan
| | - Susumu Uehara
- Center for Gene Research, Nagoya University, Nagoya, 464-8602, Japan
| | - William G. Albers
- Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA
| | | | - Shogo Ito
- Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Takamasa Suzuki
- Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, Kasugai, 487-8501, Japan
| | - Takakazu Matsuura
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan
| | - Izumi C. Mori
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan
| | - Nobutaka Mitsuda
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Daisuke Kurihara
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, 464-8601, Japan
- Institute for Advanced Research (IAR), Nagoya University, Nagoya, 464-8601, Japan
| | - Tomonao Matsushita
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Young Hun Song
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Korea
| | - Yoshikatsu Sato
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, 464-8601, Japan
| | - Mika Nomoto
- Center for Gene Research, Nagoya University, Nagoya, 464-8602, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
| | - Yasuomi Tada
- Center for Gene Research, Nagoya University, Nagoya, 464-8602, Japan
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
| | - Kousuke Hanada
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, 820-8502, Japan
| | - Josh T. Cuperus
- Department of Genome Sciences, University of Washington, Seattle, Washington, 98195-5065, USA
| | - Christine Queitsch
- Department of Genome Sciences, University of Washington, Seattle, Washington, 98195-5065, USA
- Brotman Baty Institute for Precision Medicine, University of Washington, Seattle, Washington, 98195-8047, USA
| | - Takato Imaizumi
- Department of Biology, University of Washington, Seattle, Washington, 98195-1800, USA
- Center for Gene Research, Nagoya University, Nagoya, 464-8602, Japan
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Norppa AJ, Chowdhury I, van Rooijen LE, Ravantti JJ, Snel B, Varjosalo M, Frilander MJ. Distinct functions for the paralogous RBM41 and U11/U12-65K proteins in the minor spliceosome. Nucleic Acids Res 2024; 52:4037-4052. [PMID: 38499487 DOI: 10.1093/nar/gkae070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/19/2024] [Accepted: 03/11/2024] [Indexed: 03/20/2024] Open
Abstract
Here, we identify RBM41 as a novel unique protein component of the minor spliceosome. RBM41 has no previously recognized cellular function but has been identified as a paralog of U11/U12-65K, a known unique component of the U11/U12 di-snRNP. Both proteins use their highly similar C-terminal RRMs to bind to 3'-terminal stem-loops in U12 and U6atac snRNAs with comparable affinity. Our BioID data indicate that the unique N-terminal domain of RBM41 is necessary for its association with complexes containing DHX8, an RNA helicase, which in the major spliceosome drives the release of mature mRNA from the spliceosome. Consistently, we show that RBM41 associates with excised U12-type intron lariats, is present in the U12 mono-snRNP, and is enriched in Cajal bodies, together suggesting that RBM41 functions in the post-splicing steps of the minor spliceosome assembly/disassembly cycle. This contrasts with U11/U12-65K, which uses its N-terminal region to interact with U11 snRNP during intron recognition. Finally, while RBM41 knockout cells are viable, they show alterations in U12-type 3' splice site usage. Together, our results highlight the role of the 3'-terminal stem-loop of U12 snRNA as a dynamic binding platform for the U11/U12-65K and RBM41 proteins, which function at distinct stages of the assembly/disassembly cycle.
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Affiliation(s)
- Antto J Norppa
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Iftekhar Chowdhury
- Molecular Systems Biology Research Group and Proteomics Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Laura E van Rooijen
- Theoretical Biology and Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Janne J Ravantti
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Markku Varjosalo
- Molecular Systems Biology Research Group and Proteomics Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Mikko J Frilander
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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Bai R, Yuan M, Zhang P, Luo T, Shi Y, Wan R. Structural basis of U12-type intron engagement by the fully assembled human minor spliceosome. Science 2024; 383:1245-1252. [PMID: 38484052 DOI: 10.1126/science.adn7272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 02/09/2024] [Indexed: 03/19/2024]
Abstract
The minor spliceosome, which is responsible for the splicing of U12-type introns, comprises five small nuclear RNAs (snRNAs), of which only one is shared with the major spliceosome. In this work, we report the 3.3-angstrom cryo-electron microscopy structure of the fully assembled human minor spliceosome pre-B complex. The atomic model includes U11 small nuclear ribonucleoprotein (snRNP), U12 snRNP, and U4atac/U6atac.U5 tri-snRNP. U11 snRNA is recognized by five U11-specific proteins (20K, 25K, 35K, 48K, and 59K) and the heptameric Sm ring. The 3' half of the 5'-splice site forms a duplex with U11 snRNA; the 5' half is recognized by U11-35K, U11-48K, and U11 snRNA. Two proteins, CENATAC and DIM2/TXNL4B, specifically associate with the minor tri-snRNP. A structural analysis uncovered how two conformationally similar tri-snRNPs are differentiated by the minor and major prespliceosomes for assembly.
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Affiliation(s)
- Rui Bai
- Research Center for Industries of the Future, Key Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China
| | - Meng Yuan
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Pu Zhang
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ting Luo
- Research Center for Industries of the Future, Key Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China
| | - Yigong Shi
- Research Center for Industries of the Future, Key Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ruixue Wan
- Research Center for Industries of the Future, Key Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310024, Zhejiang Province, China
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Ding Z, Meng YR, Fan YJ, Xu YZ. Roles of minor spliceosome in intron recognition and the convergence with the better understood major spliceosome. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1761. [PMID: 36056453 DOI: 10.1002/wrna.1761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 06/06/2022] [Accepted: 08/06/2022] [Indexed: 01/31/2023]
Abstract
Catalyzed by spliceosomes in the nucleus, RNA splicing removes intronic sequences from precursor RNAs in eukaryotes to generate mature RNA, which also significantly increases proteome complexity and fine-tunes gene expression. Most metazoans have two coexisting spliceosomes; the major spliceosome, which removes >99.5% of introns, and the minor spliceosome, which removes far fewer introns (only 770 at present have been predicted in the human genome). Both spliceosomes are large and dynamic machineries, each consisting of five small nuclear RNAs (snRNAs) and more than 100 proteins. However, the dynamic assembly, catalysis, and protein composition of the minor spliceosome are still poorly understood. With different splicing signals, minor introns are rare and usually distributed alone and flanked by major introns in genes, raising questions of how they are recognized by the minor spliceosome and how their processing deals with the splicing of neighboring major introns. Due to large numbers of introns and close similarities between the two machinery, cooperative, and competitive recognition by the two spliceosomes has been investigated. Functionally, many minor-intron-containing genes are evolutionarily conserved and essential. Mutations in the minor spliceosome exhibit a variety of developmental defects in plants and animals and are linked to numerous human diseases. Here, we review recent progress in the understanding of minor splicing, compare currently known components of the two spliceosomes, survey minor introns in a wide range of organisms, discuss cooperation and competition of the two spliceosomes in splicing of minor-intron-containing genes, and contributions of minor splicing mutations in development and diseases. This article is categorized under: RNA Processing > Processing of Small RNAs RNA Processing > Splicing Mechanisms RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.
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Affiliation(s)
- Zhan Ding
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China.,Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yan-Ran Meng
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
| | - Yu-Jie Fan
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
| | - Yong-Zhen Xu
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
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