{"title":"RNA加工/修饰酶在拟南芥对热精胺的反应中起关键作用","authors":"Mitsuru Saraumi, Takahiro Tanaka, Daiki Koyama, Yoshitaka Nishi, Yoshihiro Takahashi, Hiroyasu Motose, Taku Takahashi","doi":"10.1111/tpj.70476","DOIUrl":null,"url":null,"abstract":"<p>Thermospermine is involved in negative regulation of xylem differentiation by enhancing the translation of mRNAs of the <i>SAC51</i> gene family in Arabidopsis (<i>Arabidopsis thaliana</i>). These mRNAs contain conserved upstream open reading frames (uORFs) that interfere with the translation of the main ORF. To investigate the mechanism by which thermospermine acts in this process, we isolated mutants insensitive to thermospermine, named ‘<i>its</i>’. We show that the four genes responsible for these mutants, <i>its1</i> to <i>its4</i>, encode: (i) a homolog of SPOUT RNA methyltransferase, (ii) an rRNA pseudouridine synthase CBF5/NAP57, (iii) a putative spliceosome disassembly factor STIPL1/NTR1, and (iv) a plant-specific RNA-binding protein PHIP1. These four mutants were found to have much higher levels of thermospermine than the wild-type. While all these mutants except <i>its1</i> appear almost normal, they enhance the dwarf phenotype of a mutant of <i>ACL5,</i> which encodes thermospermine synthase, resulting in tiny plants resembling a double knockout of <i>ACL5</i> and <i>SACL3</i>, a member of the <i>SAC51</i> family. Reporter assays revealed that GUS activity from the CaMV 35S promoter-<i>SAC51</i> 5′-GUS fusion construct was significantly reduced in <i>its1</i> and <i>its4</i> or not affected in <i>its2</i> and <i>its3</i>, while it was slightly increased in <i>its1</i>, <i>its3</i>, and <i>its4</i>, or not changed in <i>its2</i> by thermospermine. These findings underscore the critical role of RNA processing and modification in the thermospermine-dependent translational regulation of uORF-containing transcripts.</p>","PeriodicalId":233,"journal":{"name":"The Plant Journal","volume":"123 5","pages":""},"PeriodicalIF":5.7000,"publicationDate":"2025-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/tpj.70476","citationCount":"0","resultStr":"{\"title\":\"RNA processing/modifying enzymes play key roles in the response to thermospermine in Arabidopsis thaliana\",\"authors\":\"Mitsuru Saraumi, Takahiro Tanaka, Daiki Koyama, Yoshitaka Nishi, Yoshihiro Takahashi, Hiroyasu Motose, Taku Takahashi\",\"doi\":\"10.1111/tpj.70476\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Thermospermine is involved in negative regulation of xylem differentiation by enhancing the translation of mRNAs of the <i>SAC51</i> gene family in Arabidopsis (<i>Arabidopsis thaliana</i>). These mRNAs contain conserved upstream open reading frames (uORFs) that interfere with the translation of the main ORF. To investigate the mechanism by which thermospermine acts in this process, we isolated mutants insensitive to thermospermine, named ‘<i>its</i>’. We show that the four genes responsible for these mutants, <i>its1</i> to <i>its4</i>, encode: (i) a homolog of SPOUT RNA methyltransferase, (ii) an rRNA pseudouridine synthase CBF5/NAP57, (iii) a putative spliceosome disassembly factor STIPL1/NTR1, and (iv) a plant-specific RNA-binding protein PHIP1. These four mutants were found to have much higher levels of thermospermine than the wild-type. While all these mutants except <i>its1</i> appear almost normal, they enhance the dwarf phenotype of a mutant of <i>ACL5,</i> which encodes thermospermine synthase, resulting in tiny plants resembling a double knockout of <i>ACL5</i> and <i>SACL3</i>, a member of the <i>SAC51</i> family. Reporter assays revealed that GUS activity from the CaMV 35S promoter-<i>SAC51</i> 5′-GUS fusion construct was significantly reduced in <i>its1</i> and <i>its4</i> or not affected in <i>its2</i> and <i>its3</i>, while it was slightly increased in <i>its1</i>, <i>its3</i>, and <i>its4</i>, or not changed in <i>its2</i> by thermospermine. These findings underscore the critical role of RNA processing and modification in the thermospermine-dependent translational regulation of uORF-containing transcripts.</p>\",\"PeriodicalId\":233,\"journal\":{\"name\":\"The Plant Journal\",\"volume\":\"123 5\",\"pages\":\"\"},\"PeriodicalIF\":5.7000,\"publicationDate\":\"2025-09-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1111/tpj.70476\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"The Plant Journal\",\"FirstCategoryId\":\"2\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1111/tpj.70476\",\"RegionNum\":1,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"PLANT SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Plant Journal","FirstCategoryId":"2","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/tpj.70476","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PLANT SCIENCES","Score":null,"Total":0}
RNA processing/modifying enzymes play key roles in the response to thermospermine in Arabidopsis thaliana
Thermospermine is involved in negative regulation of xylem differentiation by enhancing the translation of mRNAs of the SAC51 gene family in Arabidopsis (Arabidopsis thaliana). These mRNAs contain conserved upstream open reading frames (uORFs) that interfere with the translation of the main ORF. To investigate the mechanism by which thermospermine acts in this process, we isolated mutants insensitive to thermospermine, named ‘its’. We show that the four genes responsible for these mutants, its1 to its4, encode: (i) a homolog of SPOUT RNA methyltransferase, (ii) an rRNA pseudouridine synthase CBF5/NAP57, (iii) a putative spliceosome disassembly factor STIPL1/NTR1, and (iv) a plant-specific RNA-binding protein PHIP1. These four mutants were found to have much higher levels of thermospermine than the wild-type. While all these mutants except its1 appear almost normal, they enhance the dwarf phenotype of a mutant of ACL5, which encodes thermospermine synthase, resulting in tiny plants resembling a double knockout of ACL5 and SACL3, a member of the SAC51 family. Reporter assays revealed that GUS activity from the CaMV 35S promoter-SAC51 5′-GUS fusion construct was significantly reduced in its1 and its4 or not affected in its2 and its3, while it was slightly increased in its1, its3, and its4, or not changed in its2 by thermospermine. These findings underscore the critical role of RNA processing and modification in the thermospermine-dependent translational regulation of uORF-containing transcripts.
期刊介绍:
Publishing the best original research papers in all key areas of modern plant biology from the world"s leading laboratories, The Plant Journal provides a dynamic forum for this ever growing international research community.
Plant science research is now at the forefront of research in the biological sciences, with breakthroughs in our understanding of fundamental processes in plants matching those in other organisms. The impact of molecular genetics and the availability of model and crop species can be seen in all aspects of plant biology. For publication in The Plant Journal the research must provide a highly significant new contribution to our understanding of plants and be of general interest to the plant science community.