Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia.
Epigenetics Laboratory, Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia.
Cells. 2019 Sep 5;8(9):1030. doi: 10.3390/cells8091030.
H3K9 methylation is known to play a critical role in gene silencing. This modification is established and maintained by several enzymes, but relationships between them are not fully understood. In the present study, we decipher the interplay between two H3K9-specific histone methyltransferases, SU(VAR)3-9 and SETDB1. We asked whether SETDB1 is required for targeting of SU(VAR)3-9. Using DamID-seq, we obtained SU(VAR)3-9 binding profiles for the chromosomes from larval salivary glands and germline cells from adult females, and compared profiles between the wild type and SETDB1-mutant backgrounds. Our analyses indicate that the vast majority of single copy genes in euchromatin are targeted by SU(VAR)3-9 only in the presence of SETDB1, whereas SU(VAR)3-9 binding at repeated sequences in heterochromatin is largely SETDB1-independent. Interestingly, piRNA clusters 42AB and 38C in salivary gland chromosomes bind SU(VAR)3-9 regardless of SETDB1, whereas binding to the same regions in the germline cells is SETDB1-dependent. In addition, we compared SU(VAR)3-9 profiles in female germline cells at different developmental stages (germarium cells in juvenile ovaries and mature nurse cells). It turned out that SU(VAR)3-9 binding is influenced both by the presence of SETDB1, as well as by the differentiation stage.
H3K9 甲基化被认为在基因沉默中起着关键作用。这种修饰是由几种酶建立和维持的，但它们之间的关系尚未完全了解。在本研究中，我们揭示了两种 H3K9 特异性组蛋白甲基转移酶 SU(VAR)3-9 和 SETDB1 之间的相互作用。我们询问 SETDB1 是否需要靶向 SU(VAR)3-9。使用 DamID-seq，我们获得了来自幼虫唾液腺和成年雌性生殖细胞的染色体上的 SU(VAR)3-9 结合图谱，并在野生型和 SETDB1 突变体背景之间比较了图谱。我们的分析表明，在常染色质中，绝大多数单拷贝基因仅在存在 SETDB1 的情况下才被 SU(VAR)3-9 靶向，而在异染色质中的重复序列上的 SU(VAR)3-9 结合在很大程度上是 SETDB1 独立的。有趣的是，唾液腺染色体上的 piRNA 簇 42AB 和 38C 无论 SETDB1 如何都与 SU(VAR)3-9 结合，而在生殖细胞中的相同区域的结合则依赖于 SETDB1。此外，我们比较了不同发育阶段（幼年卵巢中的生殖腺细胞和成熟的滋养细胞）的雌性生殖细胞中的 SU(VAR)3-9 图谱。结果表明，SU(VAR)3-9 结合既受 SETDB1 的存在影响，也受分化阶段的影响。
