Plant Molecular Biology 53: 759–769, 2003.
© 2004 Kluwer Academic Publishers. Printed in the Netherlands.
Fertilization induces strong accumulation of a histone deacetylase (HD2)
and of other chromatin-remodeling proteins in restricted areas of the
, Sier-Ching Chantha
eve Major and Daniel P. Matton
Institut de Recherche en Biologie V´eg´etale, D´epartement de Sciences Biologiques, Universit´e de Montr´eal,
4101 Sherbrooke est, Montr´eal, Qu´ebec, Canada H1X 2B2 (
author for correspondence; e-mail
These authors contributed equally to this work
Received 7 August 2003; accepted in revised form 17 November 2003
Key words: chromatin remodeling, histone deacetylase, MYST histone acetyltransferase, plant fertilization, SAP
18, SWI/SNF, U12-type intron
Fertilization triggers a unique and complex developmental program leading to embryogenesis and seed set. Re-
cently, mutations affecting chromatin-remodeling enzymes in plants have shown their key roles in development as
demonstrated before in animal cells. Using a negative selection screen to isolate genes expressed in ovary tissues
upon fertilization, we have identiﬁed a histone deacetylase gene (named ScHD2a) of the plant-speciﬁc HD2 family,
which is predominantly expressed in ovaries of the self-incompatible species Solanum chacoense. The ScHD2a is
the probable orthologue of the Arabidopsis thaliana AtHD2a gene, which upon antisense suppression leads to
aborted seeds formation. Transcription of the ScHD2a gene is strongly triggered by fertilization and transcripts
accumulate predominantly in the micropylar region of the ovule’s integument. Interestingly, this fertilization-
induced accumulation pattern was also observed for other genes involved in transcriptional repression but not for a
MYST-family histone acetyltransferase. The strong increase in ScHD2a mRNA levels in ovules after fertilization
suggests an important and localized role for transcriptional repression in seed development, and indicates why
silencing of the AtHD2a gene leads to aborted seed formation.
Abbreviations: HAT, Histone AcetylTransferase; HDAC, Histone Deacetylase.
Chromatin remodeling by acetylation and deacetyla-
tion plays an important role in gene regulation through
the post-translational modiﬁcation of histones, either
transiently in promoter-proximal nucleosomes, or for
longer-term modulation over large chromatin domains
(Turner, 2000). The overall pattern of histone modi-
ﬁcations is proposed to constitute a code, the histone
code, that deﬁnes the nature of the surrounding chro-
matin in either a repressive or an active state (Strahl
The nucleotide sequence data reported will appear in the Gen-
Bank, EMBL and DDBJ Nucleotide Sequence Databases under
the accession numbers AY346455 (ScHD2a), AY346456 (ScP18),
AY346457 (ScSWIb), AY346458 (ScHAT) and AY346459 (ScH4).
and Allis, 2000). The basic unit of chromatin, the
nucleosome, is composed of a histone octamer core
that contains a total of about 26 highly conserved po-
tentially acetylated lysine residues. Crystallographic
analysis has revealed that the N-terminal tail of his-
tones protrude from the octamer (Luger et al., 1997).
Histone acetyltransferases (HATs) transfer the acetyl
moiety of acetyl-CoA to the ε-amino group within this
N-terminal extension; this reaction can be reversed
by the action of histone deacetylases (HDACs). It
has been demonstrated that HDACs can interact with
speciﬁc DNA-binding activator or repressor proteins,
thereby modulating transcriptional activity of speciﬁc
promoters by locally changing chromatin structure
(Heinzel et al., 1997; Pazin and Kadonaga, 1997).