Figure 8.

HLP1 is required for epigenetic modifications at the promoters of HS genes and positively regulates their transcription. A, ChIP assays of HSF and HSP genes. Seven-d–old MS-grown Arabidopsis Col-0 and hlp1 seedlings were treated with HS at 37°C for 3 h. ChIP-qPCR of immunoprecipitated promoter fragments containing Cis-acting HSEs was performed. Amount of immunoprecipitated promoter DNA was calculated by comparing samples treated without or with anti-Histone H3K (9+14+18+23+27) acetyl antibody. CT values without and with anti-Histone H3K (9+14+18+23+27) acetyl antibody were normalized by input control. Copia-like retrotransposon (TA3) with highly heterochromatinized DNA has been used as a control in the ChIP assay. Data shown are representative of two biological replicates. Experiments were repeated two times with similar results. Ctrl, control. B, Comparison of RT-qPCR showing expression profile of HS genes in Col-0, hlp1 mutant, and 35SCaMV::HLP1 (OE2) transgenic seedlings in the presence of Glc. Five-d–old Col-0, hlp1, and OE2 seedlings were starved for 24 h and then transferred to Glc-free (0% Glc) and Glc-containing (3% Glc) liquid MS medium for 3 h. Data shown are representative of two biological replicates. Experiments were repeated two times with similar results. Error bars = sd (Student’s t test, P < 0.05; *control versus treatment; **wild type versus mutant/overexpression).