The CCR4-NOT complex is a highly conserved,multifunctional machinery controlling mRNA metabolism.Its components have been implicated in several aspects of mRNA and protein expression,including transcription initiation...The CCR4-NOT complex is a highly conserved,multifunctional machinery controlling mRNA metabolism.Its components have been implicated in several aspects of mRNA and protein expression,including transcription initiation,elongation,mRNA degradation,ubiquitination,and protein modification.In this review,we will focus on the role of the CCR4-NOT complex in mRNA degradation.The complex contains two types of deadenylase enzymes,one belonging to the DEDD-type family and one belonging to the EEP-type family,which shorten the poly(A)tails of mRNA.We will review the present state of structure-function analyses into the CCR4-NOT deadenylases and summarize current understanding of their roles in mRNA degradation.We will also review structural and functional work on the Tob/BTG family of proteins,which are known to interact with the CCR4-NOT complex and which have been reported to suppress deadenylase activity in vitro.展开更多
The CCR4-NOT complex has been shown to have multiple roles in mRNA metabolism, including that of transcriptional elongation, mRNA transport, and nuclear exosome function, but the primary function of CCR4 and CAF1 is i...The CCR4-NOT complex has been shown to have multiple roles in mRNA metabolism, including that of transcriptional elongation, mRNA transport, and nuclear exosome function, but the primary function of CCR4 and CAF1 is in the deadenylation and degradation of cytoplasmic mRNA. As previous genetic analysis supported an interaction between SPT5, known to be involved in transcriptional elongation, and that of CCR4, the physical association of SPT5 with CCR4 was examined. A two-hybrid screen utilizing the deadenylase domain of CCR4 as a bait identified SPT5 as a potential interacting protein. SPT5 at its physiological concentration was shown to immunoprecipitate CCR4 and CAF1, and in vitro purified SPT5 specifically could bind to CAF1 and the deadenylase domain of CCR4. We additionally demonstrated that mutations in SPT5 or an spt4 deletion slowed the rate of mRNA degradation, a phenotype associated with defects in the CCR4 mRNA deadenylase complex. Yet, unlike ccr4 and caf1 deletions, spt5 and spt4 defects displayed little effect on the rate of deadenylation. They also did not affect decapping or 5' - 3' degradation of mRNA. These results suggest that the interactions between SPT5/SPT4 and the CCR4-NOT complex are probably the consequences of effects involving nuclear events and do not involve the primary role of CCR4 in mRNA deadenylation and turnover.展开更多
Suppression of the effects of an spt10 mutation on ADH2 expression is a phenotype shared by a small number of genes whose protein products are either components of the CCR4-NOT complex required for mRNA deadenylation ...Suppression of the effects of an spt10 mutation on ADH2 expression is a phenotype shared by a small number of genes whose protein products are either components of the CCR4-NOT complex required for mRNA deadenylation and degradation (CCR4, CAF1, NOT4) or have been shown to interact with the complex (DBF2, SRB9, SRB10). In this work, we conducted a screen for additional suppressors of spt10 at ADH2 to identify new factors related to CCR4 function. In addition to reisolating ccr4 and caf1 alleles, three previously unidentified suppressors of spt10 were obtained: ebs1, lsm6, and nup159. These three genes are known or presumed to affect mRNA export or degradation. Mutations in EBS1, LSM6 and NUP159 not only suppressed spt10-induced ADH2 expression but also, like ccr4 and caf1 defects, reduced the ability of ADH2 to derepress. None of these defects affected the expression of CCR4-NOT complex components or the formation of the CCR4-NOT complex. The reduced ADH2 expression was also not the result of increased degradation of ADH2 mRNA, as the lsm6 and nup159 alleles, like that of a ccr4 deletion, actually slowed ADH2 degradation. Our results indicate that alterations in factors that slow mRNA degradation or affect mRNA transport may also interfere with the synthesis of mRNA and suggest an integration of such events in gene expression.展开更多
Regulation of RNA stability plays a crucial role in gene expression control.Deadenylation is the initial rate-limiting step for the majority of RNA decay events.Here,we show that RING finger protein 219(RNF219)interac...Regulation of RNA stability plays a crucial role in gene expression control.Deadenylation is the initial rate-limiting step for the majority of RNA decay events.Here,we show that RING finger protein 219(RNF219)interacts with the CCR4-NOT deadenylase complex.RNF219-CCR4-NOT exhibits deadenylation activity in vitro.RNA-seq analyses identify some of the 2-cell-specific genes and the neuronal genes significantly downregulated upon RNF219 knockdown,while upregulated after depletion of the CCR4-NOT subunit CNOTIO in mouse embryonic stem(ES)cells.RNF219 depletion leads to impaired neuronal lineage commitment during ES cell differentiation.Our study suggests that RNF219 is a novel interacting partner of CCR4-NOT and required for maintenance of ES cell pluripotency.展开更多
基金This work was supported by the National Basic Research Program(973 Program)(Grant No.2007CB914301)the National Natural Science Foundation of China(Grant Nos.30221003 and 30770438)This work was also supported in part by the Global COE Program(Integrative Life Science Based on the Study of Biosignaling Mechanisms),MEXT,Japan.
文摘The CCR4-NOT complex is a highly conserved,multifunctional machinery controlling mRNA metabolism.Its components have been implicated in several aspects of mRNA and protein expression,including transcription initiation,elongation,mRNA degradation,ubiquitination,and protein modification.In this review,we will focus on the role of the CCR4-NOT complex in mRNA degradation.The complex contains two types of deadenylase enzymes,one belonging to the DEDD-type family and one belonging to the EEP-type family,which shorten the poly(A)tails of mRNA.We will review the present state of structure-function analyses into the CCR4-NOT deadenylases and summarize current understanding of their roles in mRNA degradation.We will also review structural and functional work on the Tob/BTG family of proteins,which are known to interact with the CCR4-NOT complex and which have been reported to suppress deadenylase activity in vitro.
文摘The CCR4-NOT complex has been shown to have multiple roles in mRNA metabolism, including that of transcriptional elongation, mRNA transport, and nuclear exosome function, but the primary function of CCR4 and CAF1 is in the deadenylation and degradation of cytoplasmic mRNA. As previous genetic analysis supported an interaction between SPT5, known to be involved in transcriptional elongation, and that of CCR4, the physical association of SPT5 with CCR4 was examined. A two-hybrid screen utilizing the deadenylase domain of CCR4 as a bait identified SPT5 as a potential interacting protein. SPT5 at its physiological concentration was shown to immunoprecipitate CCR4 and CAF1, and in vitro purified SPT5 specifically could bind to CAF1 and the deadenylase domain of CCR4. We additionally demonstrated that mutations in SPT5 or an spt4 deletion slowed the rate of mRNA degradation, a phenotype associated with defects in the CCR4 mRNA deadenylase complex. Yet, unlike ccr4 and caf1 deletions, spt5 and spt4 defects displayed little effect on the rate of deadenylation. They also did not affect decapping or 5' - 3' degradation of mRNA. These results suggest that the interactions between SPT5/SPT4 and the CCR4-NOT complex are probably the consequences of effects involving nuclear events and do not involve the primary role of CCR4 in mRNA deadenylation and turnover.
文摘Suppression of the effects of an spt10 mutation on ADH2 expression is a phenotype shared by a small number of genes whose protein products are either components of the CCR4-NOT complex required for mRNA deadenylation and degradation (CCR4, CAF1, NOT4) or have been shown to interact with the complex (DBF2, SRB9, SRB10). In this work, we conducted a screen for additional suppressors of spt10 at ADH2 to identify new factors related to CCR4 function. In addition to reisolating ccr4 and caf1 alleles, three previously unidentified suppressors of spt10 were obtained: ebs1, lsm6, and nup159. These three genes are known or presumed to affect mRNA export or degradation. Mutations in EBS1, LSM6 and NUP159 not only suppressed spt10-induced ADH2 expression but also, like ccr4 and caf1 defects, reduced the ability of ADH2 to derepress. None of these defects affected the expression of CCR4-NOT complex components or the formation of the CCR4-NOT complex. The reduced ADH2 expression was also not the result of increased degradation of ADH2 mRNA, as the lsm6 and nup159 alleles, like that of a ccr4 deletion, actually slowed ADH2 degradation. Our results indicate that alterations in factors that slow mRNA degradation or affect mRNA transport may also interfere with the synthesis of mRNA and suggest an integration of such events in gene expression.
基金Studies in this manuscript were supported by funds provided by the National Natural Science Foundation of China(31671343 and 31970617 to C.L.,31970626 to Z.L.,31700718 to D.H.)National Key R&D Program of China(2018YFA0800100 to C.L.)+2 种基金Natural Science Foundation of Jiangsu Province of China(BK20170020 to Z.L.,BK20170663 to D.H.)China Postdoctoral Science Foundation(2018M630492 to D.H.)Scientific Research Foundation of the Graduate School of Southeast University(YBPY1888 to Y.W.).
文摘Regulation of RNA stability plays a crucial role in gene expression control.Deadenylation is the initial rate-limiting step for the majority of RNA decay events.Here,we show that RING finger protein 219(RNF219)interacts with the CCR4-NOT deadenylase complex.RNF219-CCR4-NOT exhibits deadenylation activity in vitro.RNA-seq analyses identify some of the 2-cell-specific genes and the neuronal genes significantly downregulated upon RNF219 knockdown,while upregulated after depletion of the CCR4-NOT subunit CNOTIO in mouse embryonic stem(ES)cells.RNF219 depletion leads to impaired neuronal lineage commitment during ES cell differentiation.Our study suggests that RNF219 is a novel interacting partner of CCR4-NOT and required for maintenance of ES cell pluripotency.
