Strategy of Our Research

Anomalies of mice in which each component of the CCR4-NOT complex is mutated by gene targeting will be examined. Through the analysis, we will look for mRNA species whose expression is under the control of CCR4-NOT deadenylases. To help identify such mRNAs, we employ microarray analysis in conjunction with various biochemical and molecular biological methods to compare the mRNA species expressed in relevant tissues of wild-type and gene-targeted mice. For example, because CNOT7 disruption causes anomaly in spermatogenesis, we will determine targets of the CNOT7 deadenylase by comparing mRNA expression profiles in the testis between wild-type and mutant mice. The targets will be scrutinized for the presence of microRNAs binding sites and AU-rich elements in their untranslated regions. Their responsiveness to the decay of the target mRNAs is also examined. Eventually, we will determine mRNA species that are recognized by CCR4-NOT deadenylases in different tissues and in different conditions. Basing on these data as well as structural information on the CCR4-NOT components obtained from the X-ray crystallography, we will establish general mechanisms of the mRNA decay that is controlled by CCR4-NOT as well as by various factors such as microRNAs, RNA binding proteins, poly(A) binding proteins and extracellular signals.

Expected Research Achievements and Scientific Significance

In this study we will dissect anomalies caused by disruption of the CCR4-NOT deadenylases and reveal the biological importance of the CCR4-NOT deadenylases. Basing on the biological significance of the CCR4-NOT deadenylases, we will establish a novel, yet fundamental mechanism by which mRNA decay is controlled. Because regulation of gene expression is a central issue of all biological phenomena, and because gene expression largely depends on mRNA decay, the outcome of this research program would give a great impact in the basic biological sciences as well as medical sciences.