SUPPRESSOR OF FRIGIDA (SUF4) Supports Gamete Fusion via Regulating Arabidopsis EC1 Gene Expression1
In Arabidopsis, gamete fusion requires the C 2 H 2 transcription factor SUF4, which regulates the expression of the EGG CELL1 gene family. The EGG CELL1 ( EC1 ) gene family of Arabidopsis ( Arabidopsis thaliana ) comprises five members that are specifically expressed in the egg cell and redundantly...
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Published in: | Plant physiology (Bethesda) 2016-12, Vol.173 (1), p.155-166 |
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Main Authors: | , , , , , , , , , , , |
Format: | Article |
Language: | eng |
Subjects: | |
Online Access: | Get full text |
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Summary: | In Arabidopsis, gamete fusion requires the C
2
H
2
transcription factor SUF4, which regulates the expression of the EGG CELL1 gene family.
The
EGG CELL1
(
EC1
) gene family of Arabidopsis (
Arabidopsis thaliana
) comprises five members that are specifically expressed in the egg cell and redundantly control gamete fusion during double fertilization. We investigated the activity of all five
EC1
promoters in promoter-deletion studies and identified SUF4 (SUPPRESSOR OF FRIGIDA4), a C
2
H
2
transcription factor, as a direct regulator of the
EC1
gene expression. In particular, we demonstrated that SUF4 binds to all five Arabidopsis
EC1
promoters, thus regulating their expression. The down-regulation of
SUF4
in homozygous
suf4-1
ovules results in reduced
EC1
expression and delayed sperm fusion, which can be rescued by expressing SUF4-β-glucuronidase under the control of the
SUF4
promoter. To identify more gene products able to regulate
EC1
expression together with SUF4, we performed coexpression studies that led to the identification of
MOM1
(
MORPHEUS’ MOLECULE1
), a component of a silencing mechanism that is independent of DNA methylation marks. In
mom1-3
ovules, both
SUF4
and
EC1
genes are down-regulated, and
EC1
genes show higher levels of histone 3 lysine-9 acetylation, suggesting that MOM1 contributes to the regulation of
SUF4
and
EC1
gene expression. |
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ISSN: | 0032-0889 1532-2548 |