Abstract：
Oxidation of histone H3 at lysine 4 (H3K4ox) is catalyzed by lysyl oxidase homolog 2 (LOXL2). This histone modification is enriched in heterochromatin in triple-negative breast cancer (TNBC) cells and has been linked to the maintenance of compacted chromatin. However, the molecular mechanism underlying this maintenance is still unknown. Here, we show that LOXL2 interacts with RuvB-Like 1 (RUVBL1), RuvB-Like 2 (RUVBL2), Actin-like protein 6A (ACTL6A), and DNA methyltransferase 1associated protein 1 (DMAP1), a complex involved in the incorporation of the histone variant H2A.Z. Our experiments indicate that this interaction and the active form of RUVBL2 are required to maintain LOXL2-dependent chromatin compaction. Genome-wide experiments showed that H2A.Z, RUVBL2, and H3K4ox colocalize in heterochromatin regions. In the absence of LOXL2 or RUVBL2, global levels of the heterochromatin histone mark H3K9me3 were strongly reduced, and the ATAC-seq signal in the H3K9me3 regions was increased. Finally, we observed that the interplay between these series of events is required to maintain H3K4ox-enriched heterochromatin regions, which in turn is key for maintaining the oncogenic properties of the TNBC cell line tested (MDA-MB-231).
摘要：
赖氨酸4(H3K4ox)处组蛋白H3的氧化由赖氨酰氧化酶同源物2(L0XL2)催化。这种组蛋白修饰在三阴性乳腺癌（TNBC）细胞中富含异染色质，并与致密染色质的维持有关。然而,这种维持的分子机制仍然未知。这里,我们证明了LOXL2与RuvB-Like1(RUVBL1)相互作用，RuvB-Like2(RUVBL2),肌动蛋白6A（ACTL6A），和DNA甲基转移酶1相关蛋白1（DMAP1），参与组蛋白变体H2A.Z的掺入的复合物。我们的实验表明，这种相互作用和RUVBL2的活性形式是维持L0XL2依赖性染色质压实所必需的。全基因组实验表明，H2A。Z,RUVBL2和H3K4ox共定位在异染色质区域。在没有LOXL2或RUVBL2的情况下，异染色质组蛋白标记H3K9me3的整体水平大大降低，H3K9me3区域的ATAC-seq信号增加。最后,我们观察到这一系列事件之间的相互作用是维持富含H3K4ox的异染色质区域所必需的，这又是维持所测试的TNBC细胞系(MDA-MB-231)的致癌特性的关键。
