AtCPL5, a novel Ser-2-specific RNA polymerase II C-terminal domain phosphatase, positively regulates ABA and drought responses in Arabidopsis

Authors

  • Yong-Mei Jin,

    1. Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
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  • Jinwook Jung,

    1. Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
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  • Hyesung Jeon,

    1. Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
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  • So Youn Won,

    1. Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
    2. Rural Development Administration, Suwon, 441-707, Republic of Korea
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  • Yue Feng,

    1. Faculty of Molecular and Environmental Plant Science, Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843-2133, USA
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  • Jae-Sook Kang,

    1. Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju, 660-701, Republic of Korea
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  • Sang Yeol Lee,

    1. Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju, 660-701, Republic of Korea
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  • Jong-Joo Cheong,

    1. Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
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  • Hisashi Koiwa,

    1. Faculty of Molecular and Environmental Plant Science, Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843-2133, USA
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  • Minkyun Kim

    1. Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
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Author for correspondence:
Minkyun Kim
Tel: 82 2 880 4641
Email: mkkim3@snu.ac.kr

Summary

  • Arabidopsis RNA polymerase II (RNAPII) C-terminal domain (CTD) phosphatases regulate stress-responsive gene expression and plant development via the dephosphorylation of serine (Ser) residues of the CTD. Some of these phosphatases (CTD phosphatase-like 1 (CPL1) to CPL3) negatively regulate ABA and stress responses. Here, we isolated AtCPL5, a cDNA encoding a protein containing two CTD phosphatase domains (CPDs).
  • To characterize AtCPL5, we analyzed the gene expression patterns and subcellular protein localization, investigated various phenotypes of AtCPL5-overexpressors and knockout mutants involved in ABA and drought responses, performed microarray and RNA hybridization analyses using AtCPL5-overexpressors, and assessed the CTD phosphatase activities of the purified AtCPL5 and each CPD of the protein.
  • Transcripts of the nucleus-localized AtCPL5 were induced by ABA and drought. AtCPL5-overexpressors exhibited ABA-hypersensitive phenotypes (increased inhibition of seed germination, seedling growth, and stomatal aperture), lower transpiration rates upon dehydration, and enhanced drought tolerance, while the knockout mutants showed weak ABA hyposensitivity. AtCPL5 overexpression changed the expression of numerous genes, including those involved in ABA-mediated responses. In contrast to Ser-5-specific phosphatase activity of the negative stress response regulators, purified AtCPL5 and each CPD of the protein specifically dephosphorylated Ser-2 in RNAPII CTD.
  • We conclude that AtCPL5 is a unique CPL family protein that positively regulates ABA-mediated development and drought responses in Arabidopsis.

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