Tringe Susannah Green, Willis Jason, Liberatore Katie L, Ruby Stephanie W
Department of Molecular Genetics and Microbiology and Cancer Research and Treatment Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA.
Genetics. 2006 Nov;174(3):1215-28. doi: 10.1534/genetics.106.062042. Epub 2006 Sep 15.
Cellular responses to DNA damage and inhibited replication are evolutionarily conserved sets of pathways that are critical to preserving genome stability. To identify new participants in these responses, we undertook a screen for regulators that, when present on a high-copy vector, alter expression of a DNA damage-inducible RNR3-lacZ reporter construct in Saccharomyces cerevisiae. From this screen we isolated a plasmid encoding two closely related paralogs, WTM1 and WTM2, that greatly increases constitutive expression of RNR3-lacZ. Moderate overexpression of both genes together, or high-level expression of WTM2 alone from a constitutive promoter, upregulates RNR3-lacZ in the absence of DNA damage. Overexpressed, tagged Wtm2p is associated with the RNR3 promoter, indicating that this effect is likely direct. Further investigation reveals that Wtm2p and Wtm1p, previously described as regulators of meiotic gene expression and transcriptional silencing, amplify transcriptional induction of RNR3 in response to replication stress and modulate expression of genes encoding other RNR subunits.
细胞对DNA损伤和复制抑制的反应是进化上保守的一系列途径，对维持基因组稳定性至关重要。为了鉴定这些反应中的新参与者，我们进行了一项筛选，寻找调控因子，当它们存在于高拷贝载体上时，会改变酿酒酵母中DNA损伤诱导的RNR3-lacZ报告构建体的表达。通过这个筛选，我们分离出一个编码两个密切相关旁系同源物WTM1和WTM2的质粒，它们极大地增加了RNR3-lacZ的组成型表达。两个基因一起适度过表达，或者单独从组成型启动子高水平表达WTM2，在没有DNA损伤的情况下会上调RNR3-lacZ。过表达的、带有标签的Wtm2p与RNR3启动子相关联表明这种效应可能是直接的。进一步研究发现，Wtm2p和Wtm1p，以前被描述为减数分裂基因表达和转录沉默的调控因子，在对复制应激的反应中增强RNR3的转录诱导，并调节编码其他RNR亚基的基因的表达。
