He supernatant was collected. This is the pre-cleared chromatin sample.Figure 2. Expression analyses of histone methyltransferases (HMTs) in LY2409021 site Arabidopsis Cvi seeds. (A) Class I SET-domain HMTs. (B, C) Class III SET-domain HMTs. Mean of three biological replicates +/2 SE are shown. Note that the Y-axis for the RNA data is in log 10-scale. doi:10.1371/journal.pone.0051532.gRNA Extraction and cDNA SynthesisWhole seeds of Arabidopsis, yellow-cedar embryos and yellowcedar megagametophytes were ground in liquid nitrogen and totalHistone Methylation Dynamics in SeedsFigure 3. Expression analyses and histone H3 methylation pattern changes of germination-associated genes in Arabidopsis Cvi. nChIP/qPCR (left column) and expression analyses (right column); averages of three biological replicates are shown +/2 SE. ER = endosperm rupture (completion of germination). Note that the Y-axis for the RNA data is in log-scale. doi:10.1371/journal.pone.0051532.gPre-cleared chromatin (250 ml) was used per immunoprecipitation (IP). One hundred ml of the sample was used as input and left at 4uC overnight. Chromatin was immunoprecipitated with antibodies against unmodified histone H3 (Sigma Aldrich, H9289), H3K4me3 (Abcam, 8580) and H3K27me3 (Abcam, 6002), respectively. As a negative control, a mock IP with IgG (Sigma Aldrich) was performed. Thirty ml blocked A/G beads were added to each reaction and the samples rotated at 4uC overnight. The beads were then spun down and washed twice with 400 ml wash buffer (20 mM Tris/HCl pH 8.0, 0.1 SDS, 1 Triton X-100, 2 mM EDTA, PIC), containing 150 mM NaCl for 5 min at 4uC, and once with 400 ml wash buffer containing 500 mM NaCl. After the last centrifugation, the supernatant was discarded and 100 ml elution buffer (100 mM NaHCO3, 1 SDS) was added to all samples including the untreated input sample. All samples were incubated at 65uC for 10 min, centrifuged 1531364 at 4000 rpm for 1 min at room temperature and the supernatants were collected. The elution step was repeated and the eluates pooled.Purification of ChIP EluatesTen mg RNAase A (Fermentas) was added to the eluates, and the mixture was incubated for 30 min at room temperature. DNA was purified 1317923 with a nucleic acid purification kit (Epoch Lifescience) and eluted with 20 ml elution buffer. The resulting DNA solution was diluted five times and 2 ml was used as a template for qPCR.Native ChIP of Yellow-Cedar Seed and Seedling TissuesFor yellow-cedar embryos and megagametophytes as well as seedling nChIP, 60 seed parts or 20 seedlings underwent the same protocol as described for Arabidopsis in Material and Methods, with one modification. In the washing step after the IP, beads were washed twice for 10 min in low-salt wash buffer and twice for 5 min in high-salt wash buffer.Native ChIP/qPCRqPCRs using purified nChIP-DNA as a template were run in 15 ml reactions on an ABI7900HT machine with EvaGreen qPCR mastermix with ROX (abmgood). Primers (Table S1) were TA02 placedHistone Methylation Dynamics in SeedsHistone Methylation Dynamics in SeedsFigure 4. Expression analyses and histone H3 methylation pattern changes of regulators of seed maturation/dormancy in Arabidopsis Cvi. nChIP/qPCR (left column) and expression analyses (right column); averages of three biological replicates are shown +/2 SE. Numbers 1? correspond to the stages noted on the X-axis for DOG1. ER = endosperm rupture (completion of germination). Note that the Y-axis for the RNA data is in log-scale. doi:10.1371/journal.He supernatant was collected. This is the pre-cleared chromatin sample.Figure 2. Expression analyses of histone methyltransferases (HMTs) in Arabidopsis Cvi seeds. (A) Class I SET-domain HMTs. (B, C) Class III SET-domain HMTs. Mean of three biological replicates +/2 SE are shown. Note that the Y-axis for the RNA data is in log 10-scale. doi:10.1371/journal.pone.0051532.gRNA Extraction and cDNA SynthesisWhole seeds of Arabidopsis, yellow-cedar embryos and yellowcedar megagametophytes were ground in liquid nitrogen and totalHistone Methylation Dynamics in SeedsFigure 3. Expression analyses and histone H3 methylation pattern changes of germination-associated genes in Arabidopsis Cvi. nChIP/qPCR (left column) and expression analyses (right column); averages of three biological replicates are shown +/2 SE. ER = endosperm rupture (completion of germination). Note that the Y-axis for the RNA data is in log-scale. doi:10.1371/journal.pone.0051532.gPre-cleared chromatin (250 ml) was used per immunoprecipitation (IP). One hundred ml of the sample was used as input and left at 4uC overnight. Chromatin was immunoprecipitated with antibodies against unmodified histone H3 (Sigma Aldrich, H9289), H3K4me3 (Abcam, 8580) and H3K27me3 (Abcam, 6002), respectively. As a negative control, a mock IP with IgG (Sigma Aldrich) was performed. Thirty ml blocked A/G beads were added to each reaction and the samples rotated at 4uC overnight. The beads were then spun down and washed twice with 400 ml wash buffer (20 mM Tris/HCl pH 8.0, 0.1 SDS, 1 Triton X-100, 2 mM EDTA, PIC), containing 150 mM NaCl for 5 min at 4uC, and once with 400 ml wash buffer containing 500 mM NaCl. After the last centrifugation, the supernatant was discarded and 100 ml elution buffer (100 mM NaHCO3, 1 SDS) was added to all samples including the untreated input sample. All samples were incubated at 65uC for 10 min, centrifuged 1531364 at 4000 rpm for 1 min at room temperature and the supernatants were collected. The elution step was repeated and the eluates pooled.Purification of ChIP EluatesTen mg RNAase A (Fermentas) was added to the eluates, and the mixture was incubated for 30 min at room temperature. DNA was purified 1317923 with a nucleic acid purification kit (Epoch Lifescience) and eluted with 20 ml elution buffer. The resulting DNA solution was diluted five times and 2 ml was used as a template for qPCR.Native ChIP of Yellow-Cedar Seed and Seedling TissuesFor yellow-cedar embryos and megagametophytes as well as seedling nChIP, 60 seed parts or 20 seedlings underwent the same protocol as described for Arabidopsis in Material and Methods, with one modification. In the washing step after the IP, beads were washed twice for 10 min in low-salt wash buffer and twice for 5 min in high-salt wash buffer.Native ChIP/qPCRqPCRs using purified nChIP-DNA as a template were run in 15 ml reactions on an ABI7900HT machine with EvaGreen qPCR mastermix with ROX (abmgood). Primers (Table S1) were placedHistone Methylation Dynamics in SeedsHistone Methylation Dynamics in SeedsFigure 4. Expression analyses and histone H3 methylation pattern changes of regulators of seed maturation/dormancy in Arabidopsis Cvi. nChIP/qPCR (left column) and expression analyses (right column); averages of three biological replicates are shown +/2 SE. Numbers 1? correspond to the stages noted on the X-axis for DOG1. ER = endosperm rupture (completion of germination). Note that the Y-axis for the RNA data is in log-scale. doi:10.1371/journal.