Involvement of Arabidopsis HOS15 in histone deacetylation and cold tolerance

Abstract

Histone modification in chromatin is one of the key control points in gene regulation in eukaryotic cells. Protein complexes composed of histone acetyltransferase or deacetylase, WD40 repeat protein, and many other components have been implicated in this process. Here, we report the identification and functional characterization of HOS15, a WD40-repeat protein crucial for repression of genes associated with abiotic stress tolerance through histone deacetylation in Arabidopsis. HOS15 shares high sequence similarity with human transducin-beta like protein (TBL), a component of a repressor protein complex involved in histone deacetylation. Mutation of the HOS15 gene renders mutant plants hypersensitive to freezing temperatures. HOS15 is localized in the nucleus and specifically interacts with histone H4. The level of acetylated histone H4 is higher in the hos15 mutant than in WT plants. Moreover, the stress inducible RD29A promoter is hyperinduced and associated with a substantially higher level of acetylated histone H4 in the hos15 mutant under cold stress conditions. Our results suggest a critical role for gene activation/repression by histone acetylation/deacetylation in plant acclimation and tolerance to cold stress.cold responsive gene expression ͉ freezing tolerance ͉ histone H4 deacetylation ͉ WD 40 protein

A DEAD Box RNA Helicase Is Critical for Pre-mRNA Splicing, Cold-Responsive Gene Regulation, and Cold Tolerance inArabidopsis

“…Our results show that the defective splicing of SK12 and PRR5 explains at least part of the compensatory response in the rcf1-1 mutant. We have observed a similar phenomenon in hos9-1 and hos15 mutants, which accumulate higher levels of some cold-responsive genes but are hypersensitive to cold stress (Zhu et al, 2004(Zhu et al, , 2008. Unlike rcf1-1, however, hos9-1 and hos15 mutations do not affect cold induction of CBF genes.…”

“…As shown in Figures 1C and 1D, hypocotyl elongation was similar for rcf1-1 and the wild type at 21°C but was dramatically less for rcf1-1 than for the wild type at 4°C, indicating that normal function of RCF1 is required for chilling stress tolerance. We subsequently determined the freezing tolerance of rcf1-1 by two methods: an electrolyte leakage assay (Sukumaran and Weiser, 1972;Ishitani et al, 1998) and a whole-plant freezing assay (Warren et al, 1996;JagloOttosen et al, 1998;Xin and Browse, 1998;Zhu et al, 2008). The rcf1-1 plants were hypersensitive to freezing temperatures before and after cold acclimation (Figures 1E to 1G), indicating that the ability to be fully acclimated is substantially reduced in rcf1-1.…”

Opposing control by transcription factors MYB61 and MYB3 Increases Freezing Tolerance by relieving C-repeat Binding Factor suppression

“…The regulation of selected genes associated with freezing tolerance was analyzed by qRT-PCR in plants with altered MtCBF4 expression: MtCAS15, MtLTI65, MtLTI6A, MtLTI6B, and MtCOR413, as well as two WD40 repeat-like protein genes, MtYGI3 (CU651566_11) and MtYY46 (Medtr5g035980; Zhu et al, 2008). MtCBF4-overexpressing plants exhibited higher expression levels of these seven abiotic stress-related genes, and the most highly up-regulated gene was MtCAS15 (Fig.…”

Interaction between MYC2 and ETHYLENE INSENSITIVE3 Modulates Antagonism between Jasmonate and Ethylene Signaling inArabidopsis

“…The GUS gene under the control of four copies of upstream GAL4 DNA binding sites [GAL4(4x)-D1-3(4x)]was used as the reporter (Tiwari et al, 2001;Zhu et al, 2008). The firefly LUC gene under the control of 35S promoter was the internal control.…”