Cnot3-dependent mRNA deadenylation safeguards the pluripotent state
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ABSTRACT: Poly(A)-tail length and mRNA deadenylation play important roles in post-transcriptional gene regulation. Here, we report the regulation of mRNA expression, half-life, and polysome association in mouse embryonic stem cells by the Cnot3 subunit in the Ccr4-Not mRNA deadenylase complex.
Project description:Poly(A)-tail length and mRNA deadenylation play important roles in post-transcriptional gene regulation. Here, we report the regulation of mRNA expression, half-life, and polysome association in mouse embryonic stem cells by the Cnot3 subunit in the Ccr4-Not mRNA deadenylase complex. To determine the consequence of Cnot3 deletion, Cnot3 conditional knockout ESCs were first treated with DMSO (WT) or 0.1μM 4-hydroxytamoxifen (4OHT, KO). 1. In one experiment, cells were collected 3 days after the 4OHT treatment and total RNAs were extracted and sequenced to determine changes in mRNA expression. 2. In the second experiment, cells were collected 3 days after the 4OHT treatment and polysome-associated RNAs were fractionated using a published protocol, purified, and sequenced to determine changes in polysome-association. 3. In the third experiment, cells were further treated with actinomycin D (10ug/ml) 2 days after the initial 4OHT treatment. Cells were collected at 0, 4, 8 hrs after actinomycin D treatment and total RNAs were extracted and sequenced to determine changes in mRNA half-life. Two biological replicates were carried out for each experiment. RNAs were extracted using RNA purification kits from Life Technologies, and RNA-seq libraries were prepared using Illumina TruSeq RNA library preparation kit.
Project description:Decay of mRNAs initiates with shortening of the poly(A) tail. Although the CCR4-NOT complex participates in deadenylation, how it becomes activates remain obscure. We show that complete deficiency in CNOT3, subunit 3 of this complex, is lethal in mice, but that heterozygotes survive as lean mice with hepatic and adipose tissues containing reduced lipid levels. Cnot3+/- mice have enhanced metabolic rates and remain lean on high-fat diets. We further provide evidence suggesting that CNOT3, by changing its level in response to feeding conditions, affects the activity of the CCR4-NOT deadenylase against poly(A) tails of specific mRNAs coding for proteins involved in metabolism of carbohydrates and fats. Because the levels of CNOT3 protein were decreased under fasting conditions and increased upon refeeding and because CNOT3 could be a positive regulator of the CCR4-NOT deadenylase, we hypothesized that the levels of CCR4-NOT target mRNAs would be lower in fed mice than in fasted mice. We compared the gene expression profiles of fed and fasted wild-type mice. Microarray analysis revealed that approximately 1,200 mRNA transcripts were down-regulated in the livers of fed mice. Of these mRNAs, 68 corresponded to the genes up-regulated in the livers of Cnot3+/- mice and fasted wild-type mice. A large number of the 68 identified genes encoded proteins involved in metabolism, especially lipid metabolism and growth. The livers were isolated from 8-week-old fed wild-type, fasted wild-type and fasted Cnot3+/- mice (n = 2 for each genotype).
Project description:Decay of mRNAs initiates with shortening of the poly(A) tail. Although the CCR4-NOT complex participates in deadenylation, how it becomes activates remain obscure. We show that complete deficiency in CNOT3, subunit 3 of this complex, is lethal in mice, but that heterozygotes survive as lean mice with hepatic and adipose tissues containing reduced lipid levels. Cnot3+/- mice have enhanced metabolic rates and remain lean on high-fat diets. We further provide evidence suggesting that CNOT3, by changing its level in response to feeding conditions, affects the activity of the CCR4-NOT deadenylase against poly(A) tails of specific mRNAs coding for proteins involved in metabolism of carbohydrates and fats. Because the levels of CNOT3 protein were decreased under fasting conditions and increased upon refeeding and because CNOT3 could be a positive regulator of the CCR4-NOT deadenylase, we hypothesized that the levels of CCR4-NOT target mRNAs would be lower in fed mice than in fasted mice. We compared the gene expression profiles of fed and fasted wild-type mice. Microarray analysis revealed that approximately 1,200 mRNA transcripts were down-regulated in the livers of fed mice. Of these mRNAs, 68 corresponded to the genes up-regulated in the livers of Cnot3+/- mice and fasted wild-type mice. A large number of the 68 identified genes encoded proteins involved in metabolism, especially lipid metabolism and growth.
Project description:Pancreatic β-cells are responsible for production and secretion of insulin in response to increasing blood glucose levels. Therefore, defects in pancreatic β-cell function lead to hyperglycemia and diabetes mellitus. Understanding the molecular mechanisms governing β cell function is crucial for development of novel treatment strategies for this disease. The aim of this project was to investigate the role of Cnot3, part of CCR4-NOT complex, major deadenylase complex in mammals, in pancreatic β cell function. Cnot3βKO islets display decreased expression of key regulators of β cell maturation and function. Moreover, they show an increase of progenitor cell markers, β cell-disallowed genes and genes relevant to altered β cell function. Cnot3βKO islets exhibit altered deadenylation and increased mRNA stability, partly accounting for the increase of those genes. Together, these data reveal that CNOT3-mediated mRNA deadenylation and decay constitute previously unsuspected post-transcriptional mechanisms essential for β cell identity.
Project description:The physiological importance of mRNA degradation through the CCR4-NOT deadenylase has recently been highlighted. For example, mutation in CNOT3, a gene coding for sCNOT3 subunit of the CCR4-NOT complex, is found to be associated with T-cell acute lymphoblastic leukemia, T-ALL, though its contribution to other cancers has not been reported. To identify the taget mRNAs of CNOT3 in human non-small cell lung cancer (NSCLC), we performed the microarray analysis using A549 cells with and without knockdown against CNOT3.
Project description:The CCR4-NOT complex, bearing poly(A) deadenylation activity, is a highly conserved regulator that is involved in biological control; however its action mechanisms and physiological targets remain unclear. Using genetic deletion of the CNOT3 subunit of this complex in early B cell progenitors, we show that CNOT3 plays a critical role in pro- to pre-B cell transition. CNOT3 participated in controlling germline transcription, compaction of the immunoglobulin heavy chain (Igh) locus, and Igh rearrangement, and in destabilizing tumor suppressor p53 mRNA. Moreover, by genetic ablation of p53 or introduction of pre-rearranged Igh transgene, the B cell developmental defect in the Cnot3 knockout background could be partly rescued, suggesting that CCR4-NOT complex exerts critical control in B cell differentiation processes by co-utilizing transcriptional and post-transcriptional mechanisms. Pro-B cells mRNA profiles of Mb1(cre/+) and Cnot3(fl/fl)Mb1(cre/+) mice were generated by deep sequencing using Illumina HiSeq 1500
Project description:mRNA degradation critically contributes to tissue development and function as well as transcription. The CCR4-NOT complex serves as a major deadenylase that initiates mRNA degradation. We used microarrays to identify deregulated genes in the white adipose tissues lacking CNOT3, a core subunit of the CCR4-NOT complex.
Project description:The CCR4-NOT complex, bearing poly(A) deadenylation activity, is a highly conserved regulator that is involved in biological control; however its action mechanisms and physiological targets remain unclear. Using genetic deletion of the CNOT3 subunit of this complex in early B cell progenitors, we show that CNOT3 plays a critical role in pro- to pre-B cell transition. CNOT3 participated in controlling germline transcription, compaction of the immunoglobulin heavy chain (Igh) locus, and Igh rearrangement, and in destabilizing tumor suppressor p53 mRNA. Moreover, by genetic ablation of p53 or introduction of pre-rearranged Igh transgene, the B cell developmental defect in the Cnot3 knockout background could be partly rescued, suggesting that CCR4-NOT complex exerts critical control in B cell differentiation processes by co-utilizing transcriptional and post-transcriptional mechanisms.
Project description:Decay of mRNAs initiates with shortening of the poly(A) tail. Although the CCR4-NOT complex participates in deadenylation, how it becomes activates remain obscure. We show that complete deficiency in CNOT3, subunit 3 of this complex, is lethal in mice, but that heterozygotes survive as lean mice with hepatic and adipose tissues containing reduced lipid levels. Cnot3+/- mice have enhanced metabolic rates and remain lean on high-fat diets. To examine the underlying mechanisms by which CNOT3 is involved in the control of metabolic balance, we compared the gene expression profiles of wild-type and Cnot3+/- mice using Affymetrix microarray technology. We chose to analyze the liver because the CNOT3 level in the liver was affected by the feeding condition and because the liver plays a major role in glucose and lipid metabolism. The livers were isolated from 12-week-old wild-type and Cnot3+/- mice (n = 2 for each genotype).
Project description:Decay of mRNAs initiates with shortening of the poly(A) tail. Although the CCR4-NOT complex participates in deadenylation, how it becomes activates remain obscure. We show that complete deficiency in CNOT3, subunit 3 of this complex, is lethal in mice, but that heterozygotes survive as lean mice with hepatic and adipose tissues containing reduced lipid levels. Cnot3+/- mice have enhanced metabolic rates and remain lean on high-fat diets. To examine the underlying mechanisms by which CNOT3 is involved in the control of metabolic balance, we compared the gene expression profiles of wild-type and Cnot3+/- mice using Affymetrix microarray technology. We chose to analyze the liver because the CNOT3 level in the liver was affected by the feeding condition and because the liver plays a major role in glucose and lipid metabolism.