Repression of gene expression by Arabidopsis HD2 histone deacetylases

Abstract

SummaryThe four HD2 proteins of Arabidopsis thaliana (AtHD2A±D) belong to a unique class of histone deacetylases that is plant speci®c. Previously, we have demonstrated that one of the members, AtHD2A, can mediate transcriptional repression when targeted to the promoter of a reporter gene. Here, we report that AtHD2B and AtHD2C can also repress gene expression. AtHD2A and AtHD2C differ from AtHD2B and AtHD2D in the composition of their structural domains. Our data show that both structural types play a role in the repression of gene transcription. We demonstrate that AtHD2A can mediate gene repression through interactions with transcription factors in plants. By fusing AtHD2A with the DNA-binding domain of the plant transcriptional factor Pti4, the expression of a GCC box containing reporter gene was repressed. We also demonstrated repression of a GUS gene with GAL4 enhancers using transgenic plants that expressed a GAL4/AtHD2A fusion gene. Furthermore, the expression of the GAL4/AtHD2A protein using the seed-speci®c napin promoter (NAP2) and the constitutive tCUP promoter demonstrated that repression of transgenes could be achieved in a tissue-speci®c or unrestricted manner. Targeting of HD2 proteins to speci®c promoters using transcription factor DNA-binding domains may therefore provide a new technology for silencing target genes and pathways in plants as well as for assessing the function of unknown transcription factors.

Histone acetylation affects expression of cellular patterning genes in the Arabidopsis root epidermis

“…Therefore, the most straightforward interpretation of these results is that the elevated expression levels of the CPC and GL2 genes are directly affected by histone hyperacetylation. The down-regulation of WER gene expression hyperacetylation does not fit this pattern, but there are a number of cases where histone hyperacetylation decreases gene expression (29)(30)(31). As expected based on the microarray and semiquantitative RT-PCR results, no discernable changes in the PCR products of the TTG promoters were observed after TSA treatment, although a slight increase in the upstream region of acetylated H4 was detected (Fig.…”

Ribosomal Protein S6, a Target of Rapamycin, Is Involved in the Regulation of rRNA Genes by Possible Epigenetic Changes in Arabidopsis

“…Histone deacetylases and methylases control rDNA genes and thus regulate the epigenetic on/off switch (gene dosage), providing an important mechanism in the biogenesis of ribosomes (25,27). It has been demonstrated that the activity of the yeast RPD3 is required for nucleolar reorganization and RNA pol I delocalization via its association with the rDNA chromatin, which can be antagonized by TOR (13).…”

“…The Arabidopsis genome contains four isoforms of the HDT-type histone deacetylases, namely AtHD2A, AtHD2B, AtHD2C, and AtHD2D, among which AtHD2A and AtHD2B share the highest sequence homology and the apparent functional similarities (27)(28)(29). To test the specificity of interaction between RPS6 and the AtHD2B, GFP fusion construct of a fulllength RPS6 (S6FL-GFP) was co-expressed with AtHD2A in protoplasts (Fig.…”

HISTONE DEACETYLASE19 Is Involved in Jasmonic Acid and Ethylene Signaling of Pathogen Response in Arabidopsis

“…In addition, plants contain an uncommon class of HDACs, the HD2 class, which was identified in plants only (Lusser et al, 1997;Aravind and Koonin, 1998;Wu et al, 2000aWu et al, , 2003Dangl et al, 2001;Zhou et al, 2004). Studies on the mechanism of action of HDACs in plants are beginning to emerge.…”