Association of differential gene expression and higher levels of H3K9 acetylation in memory CD8⁺ T cells. (A-B) Resting memory cell differentially expressed genes are associated with high levels of H3K9 acetylation. (A) The representative gel images of one gene with high H3K9 acetylation level (KLRB1) and one control gene (SMARCC1) are shown. N indicates naive; M, memory. (B) Three memory cell differential expressed and 3 similarly expressed genes as shown by microarray (left, n = 3), the real-time RT-PCR (middle, n = 5), and H3K9 acetylation levels (right, n = 8) between naive and memory CD8⁺ T cells. The significantly increased or similarly expressed genes were selected from the microarray data. The levels of H3K9 acetylation are significantly different between the differentially and similarly expressed genes (P < .05). Data are presented as mean ratio ± SEM (log₁₀) for array and RT-PCR, and data are presented as the mean fraction of input ± SEM for H3K9 acetylation levels of naive and memory cells. (C-D) Activated memory cell differentially expressed genes are associated with high levels of H3K9 acetylation in resting memory CD8⁺ T cells. (C) The representative gel images of 4 genes with high H3K9 acetylation levels (ICOS, IFNG, IL2RA, and KLRB1) and 2 control genes (IL2RG and MYST2) are presented. (D) Nine activated memory cell highly expressed and 9 similarly expressed genes as shown by microarray (left, n = 3), the real-time RT-PCR (middle, n = 5), and H3K9 acetylation levels (right, n = 8) between naive and memory CD8⁺ T cells after 72 hours of stimulation. The significantly increased or similarly expressed genes were selected from the array data. The levels of H3K9 acetylation are significantly different between the differentially and similarly expressed genes (P < .01) in activated memory CD8⁺ T cells. Data are presented as the same as described in panel B.