9780124047457

0124047459

9780124047402

Enzymes, v. 31

Front Cover; Eukaryotic RNases and their Partners in RNA Degradation and Biogenesis, Part A; Copyright; Contents; Preface; Chapter One: Biochemistry and Function of RNA Exosomes; 1. Introduction; 2. Cellular Functions of the Exosome; 2.1. Nuclear substrates; 2.2. RNA QC by the exosome; 2.3. mRNA turnover; 2.4. Regulation of chromatin activity by the exosome; 3. Composition of Exosomes and Their Related Complexes; 3.1. Ancestors of the eukaryotic exosome; 3.2. The eukaryotic exosome; 3.3. Enzymatic activities of the eukaryotic exosome; 3.3.1. The endo/exonuclease Dis3.

3.3.2. The exonuclease Rrp63.3.3. Activities of Exo10 and Exo11; 4. Exosome Cofactors; 4.1. Mtr4: A central helicase in nuclear RNA metabolism; 4.2. The Saccharomyces cerevisiae TRAMP complex and its human counterpart; 4.3. Rrp47p/C1D; 4.4. Mpp6; 4.5. Nrd1p and Nab3p; 4.6. The NEXT complex; 4.7. The SKI complex; 5. Concluding Remarks; Acknowledgments; References; Chapter Two: Plant Exosomes and Cofactors; 1. Introduction; 2. Composition of the Plant Exosome Core Complex; 2.1. Plant exosome subunits are often encoded by duplicated genes; 2.2. The exosome core complex of A. thaliana.

2.3. Arabidopsis CSL4 is dispensable for the stability of the core complex2.4. Functional specialization of exosome core subunits?; 2.4.1. Take home message 1; 3. Exosome-Related Activities and Cofactors in Plants; 3.1. Plants may have retained a catalytically active core complex; 3.2. Three RRP6-like proteins in different intracellular compartments; 3.3. The SKI complex is conserved in plants; 3.4. The Arabidopsis MTR4 homologue is a nucleolar protein; 3.4.1. Take home message 2; 4. Impact of Exosome-Mediated Degradation in Plants.

4.1. Polyadenylated substrates of the exosome have been identified4.2. A high level of redundancy among plant RNA degradation pathways; 5. Final Remarks; References; Chapter Three: Structure and Activities of the Eukaryotic RNA Exosome; 1. Introduction; 2. Global Architecture of the Eukaryotic Exosome Core; 3. RNase PH-Like Domains Comprise a PH-Like Ring in Eukaryotic Exosomes; 4. S1 and KH Domains Cap the PH-Like Ring; 5. Rrp44, a Hydrolytic Endoribonuclease and Processive Exoribonuclease; 6. Rrp44 and the 10-Component Exosome.

7. Rrp6, a Eukaryotic Exosome Subunit with Distributive Hydrolytic Activities8. Rrp44, Rrp6, and the 11-Component Nuclear Exosome; 9. Conclusions; Acknowledgments; References; Chapter Four: TRAMP Stimulation of Exosome; 1. TRAMP Is a Cofactor of Nuclear Exosome; 2. RNA Substrate Repertoire of TRAMP; 2.1. Quality control of ribosomes and the role of TRAMP on rDNA loci; 2.2. Surveillance of stable ncRNAs; 2.3. Turnover of unstable noncoding RNAs; 3. TRAMP Biochemistry and Structure; 3.1. Structure of the TRAMP complex; 3.2. RNA-binding properties of TRAMP subunits.