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CTD Code: a Combinatorial Code for Eukaryotic Transcription
Author(s) -
Zhang Yan,
Mayfiled Joshua,
Zhang Mengmeng,
Etzkorn Felicia
Publication year - 2015
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.29.1_supplement.94.2
Subject(s) - ctd , rna polymerase ii , transcription (linguistics) , phosphorylation , epigenetics , biology , eukaryotic transcription , transcription factor , microbiology and biotechnology , chemistry , gene expression , gene , computational biology , biochemistry , promoter , oceanography , linguistics , philosophy , geology
In eukaryotes, the C‐terminal domain of RNA polymerase II (CTD) orchestrates the temporal and spatial control of transcription and is involved in the epigenetic regulation of gene expression. Errors in CTD regulation can result in cell death, cancer and severe developmental defects. The CTD executes its function as transcription template through various post‐translational modifications on its heptad repeat sequences. Recently, novel modifications on new regulatory sites of CTD have been identified, setting the stage for the possibility of combinatorial mechanisms for transcription regulation. We focused on two well‐characterized modification of CTD, namely serine phosphorylation and prolyl isomerization, and discuss the interplay between the enzymes regulating these modification states. To address this question, we developed chemical compounds that can be used to mimic the cis and trans isomer states of proline residues in the CTD and therefore probe the selectivity of CTD binding proteins that are sensitive for this subtle variation. Our results established that the selectivity of prolyl isomerization state of CTD by phosphatases results in different regulatory effects and can lead to differentiated CTD phosphorylation states and eventually, transcription outcome. In particular, the phosphatases that specially recognize the minor species of cis proline will display enhanced activity upon prolyl isomerase regulation which is essential for accurate transcription termination. The application of such chemical probes can help us understand the molecular mechanism of the interplay between different post‐translational modifications with prolyl isomerization state and how that affects the conformational status of CTD in transcription.