Functional analysis of HD2 histone deacetylase homologues in Arabidopsis thaliana

Abstract

SummaryPost-translational modi®cation of histones, in particular acetylation, is an important mechanism in the regulation of eukaryotic gene expression. Histone deacetylases are enzymes that remove acetyl groups from the core histones and play a key role in the repression of transcription. HD2 is a maize histone deacetylase, which shows no sequence homology to the histone deacetylases identi®ed from other eukaryotes. We have identi®ed two putative HD2-like histone deacetylase cDNA clones, AtHD2A and AtHD2B, from Arabidopsis thaliana by screening the expressed sequence tag database. AtHD2A and AtHD2B encode putative proteins of 246 and 305 amino acids, and share 44% and 46% amino acid identity to the maize HD2, respectively. Northern blot analysis indicated that AtHD2A was highly expressed in¯owers and young siliques of Arabidopsis plants, whereas AtHD2B was widely expressed in stems, leaves,¯owers and young siliques. AtHD2A repressed transcription when directed to a promoter containing GAL4-binding sites as a GAL4 fusion protein. Deletion of the extended acidic domain or the domain containing predicted catalytic residues of AtHD2A resulted in the loss of gene repression activity, revealing the importance of both domains to AtHD2A function. Arabidopsis plants were transformed with a gene construct comprising an AtHD2A cDNA in the antisense orientation driven by a strong constitutive promoter, ±394tCUP. Silencing of AtHD2A expression resulted in aborted seed development in transgenic Arabidopsis plants, suggesting that the AtHD2A gene product was important in the reproductive development of Arabidopsis thaliana.

Arabidopsis histone deacetylase 6: a green link to RNA silencing

“…The Arabidopsis genome encodes four members of this family, AtHDT1-4 (Pandey et al, 2002). AtHDT1 is required for reproductive development (Wu et al, 2000;Zhou et al, 2004) and, together with AtHDT2, for the establishment of leaf polarity, possibly by controlling the levels or distribution of two micro RNAs (miRNAs) involved in abaxial/adaxial axis formation (Ueno et al, 2007). AtHDT1 further controls rRNA gene dosage in Arabidopsis and modulates rRNA transcription in genetic hybrids of different Arabidopsis species, which is consistent with its nucleolar localization (Lawrence et al, 2004).…”

Impact of nucleosome dynamics and histone modifications on cell proliferation during Arabidopsis development

“…Arabidopsis histone deacetylases (HDACs) have been classified into three families (Hollender and Liu, 2008;Alinsug et al, 2009). The first one contains members homologous to the yeast RPD3 (reduced potassium deficiency 3) and HDA1 proteins; the second, the HD-tuins (HDT1 through 3), appears to be plant-specific (Wu et al, 2000;Dangl et al, 2001) and the third family contains homologs of the yeast silent information regulator 2 (Sir2), a (NAD)-dependent HDAC (Pandey et al, 2002;Hollender and Liu, 2008). The main conclusion that we can extract from the data available is that a fine balance between HAT and HDAC activities is at the core of crucial processes during plant development.…”

Mutations in the FIE and MEA Genes That Encode Interacting Polycomb Proteins Cause Parent-of-Origin Effects on Seed Development by Distinct Mechanisms

“…(D) Pattern of paternal and maternal FIE mRNA accumulation in embryos. Reciprocal crosses between Ler and RLD plants were made, and F 1 seed were harvested at 6, 7, and 8 days after pollination, cor-et al, 1997; Wu et al, 2000). However, because loss-of-function mutations in the FIE gene are not transmitted to the next generation (Table 1), it has not been possible to address this point by generating homozygous mutant fie plants to study the function of FIE during vegetative plant development.…”

“…Restriction fragments associated with maternal and paternal alleles are indicated at left. Wu et al, 2000). However, because loss-of-function mutations in the FIE gene are not transmitted to the next generation (Table 1), it has not been possible to address this point by generating homozygous mutant fie plants to study the function of FIE during vegetative plant development.…”