Variant histone H3 which replaces conventional H3 in a wide range of nucleosomes in active genes. Constitutes the predominant form of histone H3 in non-dividing cells and is incorporated into chromatin independently of DNA synthesis. Deposited at sites of nucleosomal displacement throughout transcribed genes, suggesting that it represents an epigenetic imprint of transcriptionally active chromatin. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. The nucleosome is a histone octamer containing two molecules each of H2A, H2B, H3 and H4 assembled in one H3-H4 heterotetramer and two H2A-H2B heterodimers. The octamer wraps approximately 147 bp of DNA. Acetylation is generally linked to gene activation. Acetylated to form H3K9ac (2%), H3K14 (37%), H3K18 (25%) and H3K23 (9%). Pre-existing H3K9me or H3K27me limit the possibility for histone acetylation. H3.2 shows a much higher level of steady-state acetylation than H3.1. Increased multiacetylation after exposure to NaCl. 24% of H3K4 is found under the form of H3K4me1, 6% of H3K4me2 and 19% of H3K4me3. When not under the form of H3K9ac, H3K9 is found as H3K9me1 (43%), H3K9me2 (9%) or H3K9me3 (15%). When not acetylated, H3K14, H3K18 and H3K23 are only under the form of H3K14me3 (18%), H3K18me3 (16%), and H3K23me3 (33%). 31% of H3K27 is found under the form of H3K27me1, 24% of H3K27me2 and 38% of H3K27me3. Can be phosphorylated to form H3S10ph, H3T11ph and H3S28ph (By similarity). No phosphorylation detected during salt stress. No modifications detected on H3K36 and H3K37. Belongs to the histone H3 family. To ensure consistency between histone entries, we follow the 'Brno' nomenclature for histone modifications, with positions referring to those used in the literature for the 'closest' model organism. Due to slight variations in histone sequences between organisms and to the presence of initiator methionine in UniProtKB/Swiss-Prot sequences, the actual positions of modified amino acids in the sequence generally differ. In this entry the following conventions are used: H3K4me1/2/3 = mono-, di- and trimethylated Lys-5; H3K9ac = acetylated Lys-10; H3K9me1/2/3 = mono-, di- and trimethylated Lys-10; H3S10ph = phosphorylated Ser-11; H3T11ph = phosphorylated Thr-12; H3K14ac = acetylated Lys-15; H3K14me3 = trimethylated Lys-15; H3K18ac = acetylated Lys-19; H3K18me3 = trimethylated Lys-19; H3K23ac = acetylated Lys-24; H3K23me3 = trimethylated Lys-24; H3K27me1/2/3 = mono-, di- and trimethylated Lys-28; H3S28ph = phosphorylated Ser-29; H3K36 = Lys-37; H3K37 = Lys-38.