Molecular Biology of the Ribonuclease A Gene Superfamily

在本报告期间，我们研究了GATA-1和GATA-2在激活分泌核糖核酸酶，嗜酸性粒细胞衍生的神经毒素（EDN/RNase 2）的转录中的作用。在嗜酸性粒细胞中检测到GATA-1和GATA-2的表达增强，EDN/RNase2基因延长5'启动子中两个一致的gata结合位点中的一个或两个的缺失或突变导致报告基因活性显著降低。抗体增强电泳迁移迁移和染色质免疫沉淀分析表明，GATA-1和GATA-2蛋白结合在EDN启动子中的两个功能性GATA一致序列上。有趣的是，单独沉默GATA-1对EDN/RNase2的表达没有影响；GATA-2的沉默导致丁酸诱导的HL-60克隆15细胞和来自CD34（+）造血祖细胞的分化人嗜酸性粒细胞中EDN的表达减少，GATA-1的表达也减少。同样，GATA-2的过表达导致EDN/RNase2和GATA-1的转录增强。综上所述，我们的数据表明GATA-2通过与EDN启动子的相互作用直接起作用，也通过其调节GATA-1在嗜酸性粒细胞分化中的表达的能力间接起作用（Qiu等）。生物化学学报，2009)。

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.