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Arabidopsis CPL4 is an essential Ser2‐specific CTD‐phosphatase regulating general and xenobiotic responsive gene expression (617.2)
Author(s) -
Fukudome Akihito,
Aksoy Emre,
Wu Xiaoqiang,
Kumar Krishna,
Jeong In Sil,
May Kimberly,
Russell William,
Koiwa Hisashi
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.617.2
Subject(s) - ctd , phosphatase , arabidopsis , biology , gene , serine , arabidopsis thaliana , biochemistry , xenobiotic , microbiology and biotechnology , phosphorylation , enzyme , mutant , oceanography , geology
Phosphoregulation on C‐terminal domain (CTD) of RNA polymerase II (pol II) is a pivotal mechanism to control transcription. Pol II CTD kinases and phosphatases have been extensively studied in animal and yeast, but little is known in higher plants. Arabidopsis thaliana has four CTD phosphatase‐like (CPL) proteins and knock‐down of CPL4 (CPL4RNAi line) results in severe developmental and growth defects. In the current study, we dissect the molecular and physiological functions of CPL4. Mass‐spectrometry analysis on tandem affinity purified CPL4 complex successfully identified pol II subunits. CPL4 exhibited CTD phosphatase activity with preference toward serine 2 residues in vitro and in vivo. A catalytically inactive form of CPL4 harboring an amino acid substitution in its catalytic motif strongly inhibited general gene expressions. The inhibitory activity was dependent on in BRCT, suggesting that both catalytic FCPH and BRCT domains are essential for proper function of CPL4. A set of xenobiotic stress responsive genes was up‐regulated in CPL4RNAi lines under normal condition, but upon exposure to xenobiotic stress, the expression level of those genes in wild type and CPL4RNAi was similar. Taken together, we propose Arabidopsis CPL4 as an essential Ser2‐specific CTD phosphatase, which represses xenobiotic stress response genes under normal condition.