Molecular Biology of the Ribonuclease A Gene Superfamily

在本报告期间，我们研究了 GATA-1 和 GATA-2 在激活分泌性核糖核酸酶（嗜酸性粒细胞衍生的神经毒素 (EDN/RNase 2)）转录中的作用。 在嗜酸性粒细胞中检测到 GATA-1 和 GATA-2 表达增强，EDN/RNase2 基因延伸 5' 启动子中两个共有 GATA 结合位点之一或两者的缺失或突变导致报告基因活性大幅降低。抗体增强的电泳迁移率变化和染色质免疫沉淀分析表明，GATA-1 和 GATA-2 蛋白与 EDN 启动子中的两个功能性 GATA 共有序列结合。有趣的是，单独 GATA-1 的 RNA 沉默对 EDN/RNase2 表达没有影响； GATA-2的沉默导致丁酸诱导的HL-60克隆15细胞和源自CD34(+)造血祖细胞的分化人嗜酸性粒细胞中EDN表达减少，并且GATA-1表达减少。同样，GATA-2 的过度表达导致 EDN/RNase2 和 GATA-1 的转录增强。总而言之，我们的数据表明，GATA-2 通过与 EDN 启动子相互作用直接发挥作用，也通过其在分化嗜酸性粒细胞中调节 GATA-1 表达的能力间接发挥作用 (Qiu 等人，J Biol Chem. 2009)。 另一篇出版物关注哺乳动物RNase A核糖核酸的多样性，并完成了赵伟博士在我们课题组客座教授期间的一些杰出工作。 这份手稿鉴定了啮齿动物 RNase 1 基因的一个新簇，还用于完成和纠正 GenBank 数据库中的几个错误条目（Siegel 等人 Mamm Genome，2009 年，出版中） 我继续担任 Journal of Biological Chemistry 编辑委员会成员（自 2008 年起），这很大程度上归功于我在核糖核酸酶生物学和生物化学方面的专业知识。

During this reporting period, we examined the roles of GATA-1 and GATA-2 in activating transcription of the secretory ribonuclease, the eosinophil-derived neurotoxin (EDN/RNase 2). Augmented expression of both GATA-1 and GATA-2 was detected in eosinophils and deletion or mutation of one or both of the two consensus GATA-binding sites in the extended 5' promoter of the EDN/RNase2 gene resulted in profound reduction in reporter gene activity. Antibody-augmented electrophoretic mobility shift and chromatin immunoprecipitation analyses indicate that GATA-1 and GATA-2 proteins bind to both functional GATA consensus sequences in the EDN promoter. Interestingly, RNA silencing of GATA-1 alone had no impact on EDN/RNase2 expression; silencing of GATA-2 resulted in diminished expression of EDN, and also diminished expression of GATA-1 in both butyric acid-induced HL-60 clone 15 cells and in differentiating human eosinophils derived from CD34(+) hematopoietic progenitors. Likewise, overexpression of GATA-2 in resulted in augmented transcription of both EDN/RNase2 and GATA-1. Taken together, our data suggest that GATA-2 functions directly via interactions with the EDN promoter and also indirectly, via its ability to regulate the expression of GATA-1 in differentiating eosinophils (Qiu et al. J Biol Chem. 2009). Another publication focuses on the diversity of mammalian RNase A ribonucleases, and completes some outstanding work from Dr. Wei Zhao's visiting professorship with our group. This manuscript, which identifies a novel cluster of rodent RNase 1 genes, serves also to complete and to correct several erroneous entries in GenBank database (Siegel et al. Mamm Genome, 2009, in press) I continue to serve on the Editorial Board of Journal of Biological Chemistry (since 2008), a largely due to my expertise in Ribonuclease Biology and Biochemistry.