Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
Gene. 2013 Jan 10;512(2):314-20. doi: 10.1016/j.gene.2012.10.005. Epub 2012 Oct 16.
The Peg3 gene is expressed only from the paternally inherited allele located on proximal mouse chromosome 7. The PEG3 protein encoded by this imprinted gene is predicted to bind DNA based on its multiple zinc finger motifs and nuclear localization. In the current study, we demonstrated PEG3's DNA-binding ability by characterizing its binding motif and target genes. We successfully identified target regions bound by PEG3 from mouse brain extracts using chromatin immunoprecipitation analysis. PEG3 was demonstrated to bind these candidate regions through the consensus DNA-binding motif AGTnnCnnnTGGCT. In vitro promoter assays established that PEG3 controls the expression of a given gene through this motif. Consistent with these observations, the transcriptional levels of a subset of the target genes are also affected in a mutant mouse model with reduced levels of PEG3 protein. Overall, these results confirm PEG3 as a DNA-binding protein controlling specific target genes that are involved in distinct cellular functions.
Peg3 基因仅从位于近端小鼠染色体 7 上的父系遗传等位基因表达。这个印迹基因编码的 PEG3 蛋白，根据其多个锌指结构域和核定位，预计能够与 DNA 结合。在本研究中，我们通过鉴定其结合基序和靶基因，证实了 PEG3 的 DNA 结合能力。我们成功地通过染色质免疫沉淀分析，从鼠脑提取物中鉴定出 PEG3 结合的候选区域。通过保守的 DNA 结合基序 AGTnnCnnnTGGCT，证明 PEG3 可以与这些候选区域结合。体外启动子分析表明，PEG3 通过该基序控制特定基因的表达。与这些观察结果一致，在 PEG3 蛋白水平降低的突变小鼠模型中，一部分靶基因的转录水平也受到影响。总的来说，这些结果证实了 PEG3 作为一种 DNA 结合蛋白，能够控制特定的靶基因，这些基因参与不同的细胞功能。
