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The E2F transcription factor family regulates CENH3 expression in Arabidopsis thaliana
Author(s) -
Heckmann Stefan,
Lermontova Inna,
Berckmans Barbara,
De Veylder Lieven,
Bäumlein Helmut,
Schubert Ingo
Publication year - 2011
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2011.04715.x
Subject(s) - e2f , biology , transcription factor , chromatin immunoprecipitation , histone h3 , enhancer , psychological repression , arabidopsis thaliana , regulation of gene expression , chromatin , genetics , gene , promoter , gene expression , microbiology and biotechnology , mutant
Summary To elucidate the epigenetic maintenance mechanism for functional plant centromeres, we studied transcriptional regulation of the centromere‐specific histone H3 variant CENH3 in Arabidopsis thaliana. We focused on the structure and activity of the CENH3 promoter ( CENH3 pro) and its regulation by E2F transcription factors. Use of CENH3 pro::GUS reporter gene constructs showed that CENH3 pro is active in dividing tissues, and that full expression in root meristems depends on intragenic regulatory elements within the second intron. Chromatin immunoprecipitation identified CENH3 as an E2F target gene. Transient co‐expression of a CENH3 pro::GUS reporter gene construct with various E2F transcription factors in A. thaliana protoplasts showed that E2Fa and E2Fb (preferentially with dimerization protein DPb) activate CENH3 pro. Stable over‐expression of E2Fa and E2Fb increased the CENH3 transcript level in planta , whereas over‐expression of E2Fc decreased the CENH3 transcript level. Surprisingly, mutation of the two E2F binding sites of CENH3 pro, in particular the more upstream one (E2F2), caused an increase in CENH3 pro activity, indicating E2F‐dependent transcriptional repression. CENH3 pro repression may be triggered by the interplay of typical and atypical E2Fs in a cell cycle‐dependent manner, and/or by interaction of typical E2Fs with retinoblastoma‐related (RBR) protein. We speculate that E2Fs are involved in differential transcriptional regulation of CENH3 versus H3 , as H3 promoters lack E2F binding motifs. E2F binding motifs are also present in human and Drosophila CENH3 pro regions, thus cell cycle‐dependent transcriptional regulation of CENH3 may be highly conserved.