Histone H3 variants in male gametic cells of lily and H3 methylation in mature pollen

Histones are vital structural proteins of chromatin that influence its dynamics and function. The tissue-specific expression of histone variants has been shown to regulate the expression of specific genes and genomic stability in animal systems. Here we report on the characterization of five histone H3 variants expressed in Lilium generative cell. The gcH3 and leH3 variants show unique sequence diversity by lacking a conserved lysine residue at position 9 (H3K9). The gH3 shares conserved structural features with centromeric H3 of Arabidopsis. The gH3 variant gene is strongly expressed in generative cells and gH3 histone is incorporated in to generative cell chromatin. The lysine residue of H3 at position 4 (H3K4) is highly methylated in the nuclei of generative cells of mature pollen, while methylation of H3K4 is low in vegetative cell nuclei. Taken together, these results suggest that male gametic cells of Lilium have unique chromatin state and histone H3 variants and their methylation might be involved in gene regulation of male gametic cells.Accession numbers for the sequence data The sequences reported in this paper have been deposited in the DDBJ database gcH3 GC1174 (accession no. AB195644), gH3 GC1008 (accession no. AB195646), leH3 GC1126 (accession no. AB195648), soH3-1 GC0075 (accession no. AB195650), soH3-2 GC1661 (accession no. AB195652), genomic sequence of gcH3 (accession no. AB195645), genomic sequence of gH3 (accession no. AB195647), genomic sequence of leH3 (accession no. AB195649), genomic sequence of soH3-2 (accession no. AB195651), genomic sequence of soH3-2 (accession no. AB195653).