Department of Molecular and Cellular Biology, Institute of Chemical Biology and Fundamental Medicine, Lavrentiev Ave., 8, Novosibirsk, 630090, Russia.
Chromosome Res. 2011 Feb;19(2):235-49. doi: 10.1007/s10577-011-9193-8. Epub 2011 Feb 22.
In the present work, we found that the SUUR protein is required for the SU(VAR)3-9 enzyme to bind to the salivary gland polytene chromosomes. The SuUR mutation results in loss of SU(VAR)3-9 on the chromosomes, whereas artificial expression of the SuUR gene restores its binding. The SUUR protein is also involved in methylation of the residues H3K9 and H3K27. However, mono-, di-, and tri-methylated forms of H3K9 and H3K27 behave differently in various chromosomal domains in response to the SuUR mutation. Euchromatin and chromosome 4 are almost completely deprived of mono-, di-, and tri-methylation of H3K9. In the chromocenter, mono-methylation is reduced, di-methylation shows no noticeable changes, and tri-methylation is lost. Furthermore, mono- and di-methylation of H3K27 are not influenced by the SuUR mutation, whereas tri-methylation is lost in the chromocenter. Artificial expression of the SuUR gene on the SuUR (-) background restores the pattern of methylated residues characteristic for the wild type.
在本工作中，我们发现 SUUR 蛋白是 SU(VAR)3-9 酶结合唾液腺多线染色体所必需的。SuUR 突变导致染色体上的 SU(VAR)3-9 丢失，而 SuUR 基因的人工表达则恢复其结合。SUUR 蛋白还参与 H3K9 和 H3K27 残基的甲基化。然而，H3K9 和 H3K27 的单、二和三甲基化形式在 SuUR 突变后在不同的染色体结构域中的表现不同。常染色质和染色体 4 几乎完全失去 H3K9 的单、二和三甲基化。在染色质中心，单甲基化减少，二甲基化没有明显变化，三甲基化丢失。此外，H3K27 的单甲基化和二甲基化不受 SuUR 突变的影响，而三甲基化在染色质中心丢失。在 SuUR（-）背景下人工表达 SuUR 基因恢复了野生型特征的甲基化残基模式。
