Kimura Akatsuki, Umehara Takashi, Horikoshi Masami
. Horikoshi Gene Selector Project, Exploratory Research for Advanced Technology, Japan Science and Technology Corporation, 5-9-6 Tokodai, Tsukuba, Ibaraki 300-2635, Japan.
Nat Genet. 2002 Nov;32(3):370-7. doi: 10.1038/ng993. Epub 2002 Oct 15.
Genes located in chromosomal regions near telomeres are transcriptionally silent, whereas those located in regions away from telomeres are not. Here we show that there is a gradient of acetylation of histone H4 at lysine 16 (H4-Lys16) along a yeast chromosome; this gradient ranges from a hypoacetylated state in regions near the telomere to a hyperacetylated state in more distant regions. The hyperacetylation is regulated by Sas2p, a member of the MYST-type family of histone acetylases, whereas hypoacetylation is under the control of Sir2p, a histone deacetylase. Loss of hyperacetylation is accompanied by an increase in localization of the telomere protein Sir3p and the inactivation of gene expression in telomere-distal regions. Thus, the Sas2p and Sir2p function in concert to regulate transcription in yeast, by acetylating and deacetylating H4-Lys16 in a mechanism that may be common to all eukaryotes.
位于端粒附近染色体区域的基因转录沉默，而远离端粒区域的基因则不然。我们在此表明，沿着酵母染色体存在组蛋白H4赖氨酸16（H4-Lys16）的乙酰化梯度；该梯度范围从端粒附近区域的低乙酰化状态到更远区域的高乙酰化状态。高乙酰化由组蛋白乙酰转移酶MYST家族成员Sas2p调控，而低乙酰化则受组蛋白脱乙酰酶Sir2p控制。高乙酰化的丧失伴随着端粒蛋白Sir3p定位的增加以及端粒远端区域基因表达的失活。因此，Sas2p和Sir2p协同作用以调控酵母中的转录，通过对H4-Lys16进行乙酰化和去乙酰化，其机制可能在所有真核生物中都很常见。
