Choo Jung Ha, Kim Jeong Do, Kim Joomyeong
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
BMC Genomics. 2007 Dec 31;8:479. doi: 10.1186/1471-2164-8-479.
MacroH2A1 is a histone variant that is closely associated with the repressed regions of chromosomes. A recent study revealed that this histone variant is highly enriched in the inactive alleles of Imprinting Control Regions (ICRs).
The current study investigates the potential roles of macroH2A1 in genomic imprinting by lowering the cellular levels of the macroH2A1 protein. RNAi-based macroH2A1 knockdown experiments in Neuro2A cells changed the expression levels of a subset of genes, including Peg3 and Usp29 of the Peg3 domain. The expression of these genes was down-regulated, rather than up-regulated, in response to reduced protein levels of the potential repressor macroH2A1. This down-regulation was not accompanied with changes in the DNA methylation status of the Peg3 domain.
MacroH2A1 may not function as a transcriptional repressor for this domain, but that macroH2A1 may participate in the heterochromatin formation with functions yet to be discovered.
MacroH2A1是一种组蛋白变体，与染色体的抑制区域密切相关。最近的一项研究表明，这种组蛋白变体在印记控制区域（ICR）的非活性等位基因中高度富集。
本研究通过降低MacroH2A1蛋白的细胞水平来研究MacroH2A1在基因组印记中的潜在作用。在Neuro2A细胞中基于RNAi的MacroH2A1敲低实验改变了一组基因的表达水平，包括Peg3结构域的Peg3和Usp29。响应于潜在阻遏物MacroH2A1蛋白水平的降低，这些基因的表达被下调，而非上调。这种下调并未伴随着Peg3结构域DNA甲基化状态的改变。
MacroH2A1可能并非该结构域的转录阻遏物，但MacroH2A1可能参与异染色质形成，其功能尚待发现。
