1
|
Mejía-Jaramillo AM, Fernandez GJ, Ospina-Zapata H, Murillo AM, Jimenez DE, Gómez LA, Triana-Chávez O. PUF3 RNA binding protein of Trypanosoma cruzi regulates mitochondrial morphology and function. Heliyon 2024; 10:e32810. [PMID: 39022037 PMCID: PMC11252720 DOI: 10.1016/j.heliyon.2024.e32810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 06/07/2024] [Accepted: 06/10/2024] [Indexed: 07/20/2024] Open
Abstract
The RNA-binding PUF proteins are post-transcriptional regulators found throughout the eukaryotic domain. In Trypanosoma cruzi, ten Puf genes termed Puf1 to Puf10 have been identified. Considering that the control of gene expression in this parasite is mainly at the post-transcriptional level, we characterized the PUF3 protein by knocking out and overexpressing the gene in T. cruzi epimastigotes and studied different genetic and biological features. The RNA-seq analyses in both genotypes showed significant changes in the number of regulated transcripts compared with wild-type parasites. Thus, the number of differentially expressed genes in the knockout (ΔTcPuf3) and the overexpressor (pTEXTcPuf3) were 238 and 187, respectively. In the knockout, a more significant proportion of genes was negatively regulated (166 out of 238). In contrast, in the overexpressor, positively regulated genes were predominant (149 out of 170). Additionally, when we predicted the subcellular location of the differentially expressed genes, the results revealed an important representation of nuclear genes encoding mitochondrial proteins. Therefore, we determined whether overexpression or knockout of TcPuf3 could lead to changes in both mitochondrial structure and cellular respiration. When mitochondria from ΔTcPuf3 and pTEXTcPuf3 parasites were analyzed by transmission electron microscopy (TEM), it was observed that the overexpressor had an abnormal mitochondrial morphology, evidenced by swelling. The results associated with cellular respiration showed that both the ΔTcPuf3 and pTEXTcPuf3 had a lower efficiency in routine respiration and the electron transport system capacity. Likewise, the mitochondria from overexpressing parasites showed a slight hyperpolarization. Additionally, several biological features, depending on the function of the mitochondria, were altered, such as growth, cell division, metacyclogenesis, ROS production, and response to benznidazole. In conclusion, our results suggest that although PUF3 is not an essential protein in T. cruzi, it influences mitochondrial transcripts, affecting mitochondrial morphology and function.
Collapse
Affiliation(s)
| | - Geysson Javier Fernandez
- Biología y Control de Enfermedades Infecciosas, BCEI, Universidad de Antioquia, Medellín, Colombia
| | - Hader Ospina-Zapata
- Biología y Control de Enfermedades Infecciosas, BCEI, Universidad de Antioquia, Medellín, Colombia
| | - Ana Milena Murillo
- Biología y Control de Enfermedades Infecciosas, BCEI, Universidad de Antioquia, Medellín, Colombia
| | - Dianny Elizabeth Jimenez
- Biología y Control de Enfermedades Infecciosas, BCEI, Universidad de Antioquia, Medellín, Colombia
| | - Luis A. Gómez
- Área de Ciencias Fundamentales, Universidad Eafit, Medellín, Colombia
| | - Omar Triana-Chávez
- Biología y Control de Enfermedades Infecciosas, BCEI, Universidad de Antioquia, Medellín, Colombia
| |
Collapse
|
2
|
Tian X, Volkovinskiy A, Marchisio MA. RNAi-based Boolean gates in the yeast Saccharomyces cerevisiae. Front Bioeng Biotechnol 2024; 12:1392967. [PMID: 38895554 PMCID: PMC11184144 DOI: 10.3389/fbioe.2024.1392967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/06/2024] [Indexed: 06/21/2024] Open
Abstract
Boolean gates, the fundamental components of digital circuits, have been widely investigated in synthetic biology because they permit the fabrication of biosensors and facilitate biocomputing. This study was conducted to design and construct Boolean gates in the yeast Saccharomyces cerevisiae, the main component of which was the RNA interference pathway (RNAi) that is naturally absent from the budding yeast cells. We tested different expression cassettes for the siRNA precursor (a giant hairpin sequence, a DNA fragment-flanked by one or two introns-between convergent promoters or transcribed separately in the sense and antisense directions) and placed different components under the control of the circuit inputs (i.e., the siRNA precursor or proteins such as the Dicer and the Argonaute). We found that RNAi-based logic gates are highly sensitive to promoter leakage and, for this reason, challenging to implement in vivo. Convergent-promoter architecture turned out to be the most reliable solution, even though the overall best performance was achieved with the most difficult design based on the siRNA precursor as a giant hairpin.
Collapse
Affiliation(s)
- Ximing Tian
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Andrey Volkovinskiy
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | | |
Collapse
|
3
|
Chen S, Collart MA. Membrane-associated mRNAs: A Post-transcriptional Pathway for Fine-turning Gene Expression. J Mol Biol 2024; 436:168579. [PMID: 38648968 DOI: 10.1016/j.jmb.2024.168579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 04/14/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Abstract
Gene expression is a fundamental and highly regulated process involving a series of tightly coordinated steps, including transcription, post-transcriptional processing, translation, and post-translational modifications. A growing number of studies have revealed an additional layer of complexity in gene expression through the phenomenon of mRNA subcellular localization. mRNAs can be organized into membraneless subcellular structures within both the cytoplasm and the nucleus, but they can also targeted to membranes. In this review, we will summarize in particular our knowledge on localization of mRNAs to organelles, focusing on important regulators and available techniques for studying organellar localization, and significance of this localization in the broader context of gene expression regulation.
Collapse
Affiliation(s)
- Siyu Chen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland.
| | - Martine A Collart
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland.
| |
Collapse
|
4
|
Hayashi S, Iwamoto K, Yoshihisa T. A non-canonical Puf3p-binding sequence regulates CAT5/COQ7 mRNA under both fermentable and respiratory conditions in budding yeast. PLoS One 2023; 18:e0295659. [PMID: 38100455 PMCID: PMC10723686 DOI: 10.1371/journal.pone.0295659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/23/2023] [Indexed: 12/17/2023] Open
Abstract
The Saccharomyces cerevisiae uses a highly glycolytic metabolism, if glucose is available, through appropriately suppressing mitochondrial functions except for some of them such as Fe/S cluster biogenesis. Puf3p, a Pumillio family protein, plays a pivotal role in modulating mitochondrial activity, especially during fermentation, by destabilizing its target mRNAs and/or by repressing their translation. Puf3p preferentially binds to 8-nt conserved binding sequences in the 3'-UTR of nuclear-encoded mitochondrial (nc-mitochondrial) mRNAs, leading to broad effects on gene expression under fermentable conditions. To further explore how Puf3p post-transcriptionally regulates nc-mitochondrial mRNAs in response to cell growth conditions, we initially focused on nc-mitochondrial mRNAs known to be enriched in monosomes in a glucose-rich environment. We unexpectedly found that one of the monosome-enriched mRNAs, CAT5/COQ7 mRNA, directly interacts with Puf3p through its non-canonical Puf3p binding sequence, which is generally less considered as a Puf3p binding site. Western blot analysis showed that Puf3p represses translation of Cat5p, regardless of culture in fermentable or respiratory medium. In vitro binding assay confirmed Puf3p's direct interaction with CAT5 mRNA via this non-canonical Puf3p-binding site. Although cat5 mutants of the non-canonical Puf3p-binding site grow normally, Cat5p expression is altered, indicating that CAT5 mRNA is a bona fide Puf3p target with additional regulatory factors acting through this sequence. Unlike other yeast PUF proteins, Puf3p uniquely regulates Cat5p by destabilizing mRNA and repressing translation, shedding new light on an unknown part of the Puf3p regulatory network. Given that pathological variants of human COQ7 lead to CoQ10 deficiency and yeast cat5Δ can be complemented by hCOQ7, our findings may also offer some insights into clinical aspects of COQ7-related disorders.
Collapse
Affiliation(s)
- Sachiko Hayashi
- Graduate School of Science, University of Hyogo, Ako-gun, Hyogo, Japan
| | - Kazumi Iwamoto
- Graduate School of Life Science, University of Hyogo, Ako-gun, Hyogo, Japan
| | - Tohru Yoshihisa
- Graduate School of Science, University of Hyogo, Ako-gun, Hyogo, Japan
| |
Collapse
|
5
|
Chen S, Allen G, Panasenko OO, Collart MA. Not4-dependent targeting of MMF1 mRNA to mitochondria limits its expression via ribosome pausing, Egd1 ubiquitination, Caf130, no-go-decay and autophagy. Nucleic Acids Res 2023; 51:5022-5039. [PMID: 37094076 PMCID: PMC10250226 DOI: 10.1093/nar/gkad299] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 04/11/2023] [Indexed: 04/26/2023] Open
Abstract
The Ccr4-Not complex is a conserved multi protein complex with diverse roles in the mRNA life cycle. Recently we determined that the Not1 and Not4 subunits of Ccr4-Not inversely regulate mRNA solubility and thereby impact dynamics of co-translation events. One mRNA whose solubility is limited by Not4 is MMF1 encoding a mitochondrial matrix protein. In this work we uncover a mechanism that limits MMF1 overexpression and depends upon its co-translational targeting to the mitochondria. We have named this mechanism Mito-ENCay. This mechanism relies on Not4 promoting ribosome pausing during MMF1 translation, and hence the co-translational docking of the MMF1 mRNA to mitochondria via the mitochondrial targeting sequence of the Mmf1 nascent chain, the Egd1 chaperone, the Om14 mitochondrial outer membrane protein and the co-translational import machinery. Besides co-translational Mitochondrial targeting, Mito-ENCay depends upon Egd1 ubiquitination by Not4, the Caf130 subunit of the Ccr4-Not complex, the mitochondrial outer membrane protein Cis1, autophagy and no-go-decay.
Collapse
Affiliation(s)
- Siyu Chen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
| | - George Allen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
| | - Olesya O Panasenko
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
| | - Martine A Collart
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
| |
Collapse
|
6
|
Satoh R, Tanaka T, Yoshida N, Tanaka C, Takasaki T, Sugiura R. Fission Yeast PUF Proteins Puf3 and Puf4 Are Novel Regulators of PI4P5K Signaling. Biol Pharm Bull 2023; 46:163-169. [PMID: 36724944 DOI: 10.1248/bpb.b22-00569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Phosphatidylinositol-4-phosphate 5-kinase (PI4P5K) is a highly conserved enzyme that generates phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) by phosphorylating phosphatidylinositol 4-phosphate (PI(4)P). Schizosaccharomyces pombe (S. pombe) its3-1 is a loss-of-function mutation in the essential its3+ gene that encodes a PI4P5K. Its3 regulates cell proliferation, cytokinesis, cell integrity, and membrane trafficking, but little is known about the regulatory mechanisms of Its3. To identify regulators of Its3, we performed a genetic screening utilizing the high-temperature sensitivity (TS) of its3-1 and identified puf3+ and puf4+, encoding Pumilio/PUF family RNA-binding proteins as multicopy suppressors of its3-1 cells. The deletions of the PUF domains in the puf3+ and puf4+ genes resulted in the reduced ability to suppress its3-1, suggesting that the suppression by Puf3 and Puf4 may involve their RNA-binding activities. The gene knockout of Puf4, but not that of Puf3, exacerbated the TS of its3-1. Interestingly, mutant Its3 expression levels both at mRNA and protein levels were lower than those of the wild-type (WT) Its3. Consistently, the overexpression of the mutant its3-1 gene suppressed the its3-1 phenotypes. Notably, Puf3 and Puf4 overexpression increased the mRNA and protein expression levels of both Its3 and Its3-1. Collectively, our genetic screening revealed a functional relationship between the Pumilio/PUF family RNA-binding proteins and PI4P5K.
Collapse
Affiliation(s)
- Ryosuke Satoh
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University
| | - Taemi Tanaka
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University
| | - Nobuyasu Yoshida
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University
| | - Chiaki Tanaka
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University
| | - Teruaki Takasaki
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University
| | - Reiko Sugiura
- Laboratory of Molecular Pharmacogenomics, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Kindai University
| |
Collapse
|
7
|
Organelle-targeted imaging based on fluorogen-activating RNA aptamers in living cells. Anal Chim Acta 2022; 1209:339816. [DOI: 10.1016/j.aca.2022.339816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 11/21/2022]
|
8
|
Feng H, Wan C, Zhang Z, Chen H, Li Z, Jiang H, Yin M, Dong S, Dou D, Wang Y, Zheng X, Ye W. Specific interaction of an RNA-binding protein with the 3'-UTR of its target mRNA is critical to oomycete sexual reproduction. PLoS Pathog 2021; 17:e1010001. [PMID: 34648596 PMCID: PMC8547697 DOI: 10.1371/journal.ppat.1010001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/26/2021] [Accepted: 10/03/2021] [Indexed: 01/17/2023] Open
Abstract
Sexual reproduction is an essential stage of the oomycete life cycle. However, the functions of critical regulators in this biological process remain unclear due to a lack of genome editing technologies and functional genomic studies in oomycetes. The notorious oomycete pathogen Pythium ultimum is responsible for a variety of diseases in a broad range of plant species. In this study, we revealed the mechanism through which PuM90, a stage-specific Puf family RNA-binding protein, regulates oospore formation in P. ultimum. We developed the first CRISPR/Cas9 system-mediated gene knockout and in situ complementation methods for Pythium. PuM90-knockout mutants were significantly defective in oospore formation, with empty oogonia or oospores larger in size with thinner oospore walls compared with the wild type. A tripartite recognition motif (TRM) in the Puf domain of PuM90 could specifically bind to a UGUACAUA motif in the mRNA 3′ untranslated region (UTR) of PuFLP, which encodes a flavodoxin-like protein, and thereby repress PuFLP mRNA level to facilitate oospore formation. Phenotypes similar to PuM90-knockout mutants were observed with overexpression of PuFLP, mutation of key amino acids in the TRM of PuM90, or mutation of the 3′-UTR binding site in PuFLP. The results demonstrated that a specific interaction of the RNA-binding protein PuM90 with the 3′-UTR of PuFLP mRNA at the post-transcriptional regulation level is critical for the sexual reproduction of P. ultimum. Oomycetes are a class of eukaryotic microorganisms with life cycles and growth habits similar to filamentous fungi, but are not true fungi. Although sexual reproduction, which produce oospores, is an essential stage of life cycle, the functions of critical regulators in this biological process remain unclear due to a lack of genome editing technologies and functional genomic studies in oomycetes. In this study, we developed the first CRISPR/Cas9 system-mediated gene knockout and in situ complementation methods for Pythium ultimum, a notorious oomycete pathogen that is responsible for a variety of diseases in a broad range of plant species. We further identified the Puf family RNA-binding protein PuM90 and the flavodoxin-like protein PuFLP as major functional factors involved in P. ultimum oospore formation. We proposed a new model that PuM90 acts as a stage-specific post-transcriptional regulator by specifically binding to the 3′-UTR of PuFLP and then repressing PuFLP mRNA level. This study describes new technologies and data that will help to elucidate sexual reproduction and post-transcriptional regulation in oomycetes.
Collapse
Affiliation(s)
- Hui Feng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Chuanxu Wan
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Zhichao Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Han Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Zhipeng Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Haibin Jiang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Maozhu Yin
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Suomeng Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Daolong Dou
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Xiaobo Zheng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
| | - Wenwu Ye
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Plant Immunity, Nanjing Agricultural University, Nanjing, Jiangsu, China
- The Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), Nanjing, Jiangsu, China
- * E-mail:
| |
Collapse
|
9
|
Phosphorylation of mRNA-Binding Proteins Puf1 and Puf2 by TORC2-Activated Protein Kinase Ypk1 Alleviates Their Repressive Effects. MEMBRANES 2021; 11:membranes11070500. [PMID: 34209236 PMCID: PMC8304900 DOI: 10.3390/membranes11070500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/24/2021] [Accepted: 06/29/2021] [Indexed: 01/13/2023]
Abstract
Members of the Puf family of RNA-binding proteins typically associate via their Pumilio homology domain with specific short motifs in the 3’-UTR of an mRNA and thereby influence the stability, localization and/or efficiency of translation of the bound transcript. In our prior unbiased proteome-wide screen for targets of the TORC2-stimulated protein kinase Ypk1, we identified the paralogs Puf1/Jsn1 and Puf2 as high-confidence substrates. Earlier work by others had demonstrated that Puf1 and Puf2 exhibit a marked preference for interaction with mRNAs encoding plasma membrane-associated proteins, consistent with our previous studies documenting that a primary physiological role of TORC2-Ypk1 signaling is maintenance of plasma membrane homeostasis. Here, we show, first, that both Puf1 and Puf2 are authentic Ypk1 substrates both in vitro and in vivo. Fluorescently tagged Puf1 localizes constitutively in cortical puncta closely apposed to the plasma membrane, whereas Puf2 does so in the absence of its Ypk1 phosphorylation, but is dispersed in the cytosol when phosphorylated. We further demonstrate that Ypk1-mediated phosphorylation of Puf1 and Puf2 upregulates production of the protein products of the transcripts to which they bind, with a concomitant increase in the level of the cognate mRNAs. Thus, Ypk1 phosphorylation relieves Puf1- and Puf2-mediated post-transcriptional repression mainly by counteracting their negative effect on transcript stability. Using a heterologous protein-RNA tethering and fluorescent protein reporter assay, the consequence of Ypk1 phosphorylation in vivo was recapitulated for full-length Puf1 and even for N-terminal fragments (residues 1-340 and 143-295) corresponding to the region upstream of its dimerization domain (an RNA-recognition motif fold) encompassing its two Ypk1 phosphorylation sites (both also conserved in Puf2). This latter result suggests that alleviation of Puf1-imposed transcript destabilization does not obligatorily require dissociation of Ypk1-phosphorylated Puf1 from a transcript. Our findings add new insight about how the TORC2-Ypk1 signaling axis regulates the content of plasma membrane-associated proteins to promote maintenance of the integrity of the cell envelope.
Collapse
|
10
|
Abstract
RNA movements and localization pervade biology, from embryonic development to disease. To identify RNAs at specific locations, we developed a strategy in which a uridine-adding enzyme is anchored to subcellular sites, where it directly marks RNAs with 3' terminal uridines. This localized RNA recording approach yields a record of RNA locations, and is validated through identification of RNAs localized selectively to the endoplasmic reticulum (ER) or mitochondria. We identify a broad dual localization pattern conserved from yeast to human cells, in which the same battery of mRNAs encounter both ER and mitochondria in both species, and include an mRNA encoding a key stress sensor. Subunits of many multiprotein complexes localize to both the ER and mitochondria, suggesting coordinated assembly. Noncoding RNAs in the course of RNA surveillance and processing encounter both organelles. By providing a record of RNA locations over time, the approach complements those that capture snapshots of instantaneous positions.
Collapse
|
11
|
Bhondeley M, Liu Z. Mitochondrial Biogenesis Is Positively Regulated by Casein Kinase I Hrr25 Through Phosphorylation of Puf3 in Saccharomyces cerevisiae. Genetics 2020; 215:463-482. [PMID: 32317286 PMCID: PMC7268985 DOI: 10.1534/genetics.120.303191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 04/20/2020] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial biogenesis requires coordinated expression of genes encoding mitochondrial proteins, which in Saccharomyces cerevisiae is achieved in part via post-transcriptional control by the Pumilio RNA-binding domain protein Puf3 Puf3 binds to the 3'-UTR of many messenger RNAs (mRNAs) that encode mitochondrial proteins, regulating their turnover, translation, and/or mitochondrial targeting. Puf3 hyperphosphorylation correlates with increased mitochondrial biogenesis; however, the kinase responsible for Puf3 phosphorylation is unclear. Here, we show that the casein kinase I protein Hrr25 negatively regulates Puf3 by mediating its phosphorylation. An hrr25 mutation results in reduced phosphorylation of Puf3 in vivo and a puf3 deletion mutation reverses growth defects of hrr25 mutant cells grown on medium with a nonfermentable carbon source. We show that Hrr25 directly phosphorylates Puf3, and that the interaction between Puf3 and Hrr25 is mediated through the N-terminal domain of Puf3 and the kinase domain of Hrr25 We further found that an hrr25 mutation reduces GFP expression from GFP reporter constructs carrying the 3'-UTR of Puf3 targets. Downregulation of GFP expression due to an hrr25 mutation can be reversed either by puf3Δ or by mutations to the Puf3-binding sites in the 3'-UTR of the GFP reporter constructs. Together, our data indicate that Hrr25 is a positive regulator of mitochondrial biogenesis by phosphorylating Puf3 and inhibiting its function in downregulating target mRNAs encoding mitochondrial proteins.
Collapse
Affiliation(s)
- Manika Bhondeley
- Department of Biological Sciences, University of New Orleans, Louisiana 70148
| | - Zhengchang Liu
- Department of Biological Sciences, University of New Orleans, Louisiana 70148
| |
Collapse
|
12
|
Regulation of Translation in the Protozoan Parasite Leishmania. Int J Mol Sci 2020; 21:ijms21082981. [PMID: 32340274 PMCID: PMC7215931 DOI: 10.3390/ijms21082981] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/16/2020] [Accepted: 04/20/2020] [Indexed: 01/31/2023] Open
Abstract
Leishmaniasis represents a serious health problem worldwide and drug resistance is a growing concern. Leishmania parasites use unusual mechanisms to control their gene expression. In contrast to many other species, they do not have transcriptional regulation. The lack of transcriptional control is mainly compensated by post-transcriptional mechanisms, including tight translational control and regulation of mRNA stability/translatability by RNA-binding proteins. Modulation of translation plays a major role in parasite survival and adaptation to dramatically different environments during change of host; however, our knowledge of fine molecular mechanisms of translation in Leishmania remains limited. Here, we review the current progress in our understanding of how changes in the translational machinery promote parasite differentiation during transmission from a sand fly to a mammalian host, and discuss how translational reprogramming can contribute to the development of drug resistance.
Collapse
|
13
|
Functions, mechanisms and regulation of Pumilio/Puf family RNA binding proteins: a comprehensive review. Mol Biol Rep 2019; 47:785-807. [PMID: 31643042 DOI: 10.1007/s11033-019-05142-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 10/15/2019] [Indexed: 12/16/2022]
Abstract
The Pumilio (Pum)/Puf family proteins are ubiquitously present across eukaryotes, including yeast, plants and humans. They generally bind to the 3' untranslated regions of single stranded RNA targets in a sequence specific manner and destabilize them, although a few reports suggest their role in stabilizing the target transcripts. The Pum isoforms are implicated in a wide array of biological processes including stem cell maintenance, development, ribosome biogenesis as well as human diseases. Further studies on Pum would be interesting and important to understand their evolutionarily conserved and divergent features across species, which can have potential implications in medicine, plant sciences as well as basic molecular and cell biological studies. A large number of research reports exists, pertaining to various aspects of Pum, in individual experimental systems. This review is a comprehensive summary of the functions, types, mechanism of action as well as the regulation of Pum in various species. Also, the research questions to be addressed in future are discussed.
Collapse
|
14
|
Matsuyama T. Recent developments in terminator technology in Saccharomyces cerevisiae. J Biosci Bioeng 2019; 128:655-661. [PMID: 31324384 DOI: 10.1016/j.jbiosc.2019.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/07/2019] [Accepted: 06/07/2019] [Indexed: 11/26/2022]
Abstract
Metabolically engineered microorganisms that produce useful organic compounds will be helpful for realizing a sustainable society. The budding yeast Saccharomyces cerevisiae has high utility as a metabolic engineering platform because of its high fermentation ability, non-pathogenicity, and ease of handling. When producing yeast strains that produce exogenous compounds, it is a prerequisite to control the expression of exogenous enzyme-encoding genes. Terminator region in a gene expression cassette, as well as promoter region, could be used to improve metabolically engineered yeasts by increasing or decreasing the expression of the target enzyme-encoding genes. The findings on terminators have grown rapidly in the last decade, so an overview of these findings should provide a foothold for new developments.
Collapse
|
15
|
Abstract
Cells must make careful use of the resources available to them. A key area of cellular regulation involves the biogenesis of ribosomes. Transcriptional regulation of ribosome biogenesis factor genes through alterations in histone acetylation has been well studied. This work identifies a post-transcriptional mechanism of ribosome biogenesis regulation by Puf protein control of mRNA stability. Puf proteins are eukaryotic mRNA binding proteins that play regulatory roles in mRNA degradation and translation via association with specific conserved elements in the 3' untranslated region (UTR) of target mRNAs and with degradation and translation factors. We demonstrate that several ribosome biogenesis factor mRNAs in Saccharomyces cerevisiae containing a canonical Puf4p element in their 3' UTRs are destabilized by Puf2p, Puf4, and Puf5p, yet stabilized by Puf1p and Puf3p. In the absence of all Puf proteins, these ribosome biogenesis mRNAs are destabilized by a secondary mechanism involving the same 3' UTR element. Unlike other targets of Puf4p regulation, the decay of these transcripts is not altered by carbon source. Overexpression of Puf4p results in delayed ribosomal RNA processing and altered ribosomal subunit trafficking. These results represent a novel role for Puf proteins in yeast as regulators of ribosome biogenesis transcript stability.
Collapse
Affiliation(s)
- Anthony D Fischer
- a Department of Biology , University of Missouri-St. Louis , St. Louis , MO , USA
| | - Wendy M Olivas
- a Department of Biology , University of Missouri-St. Louis , St. Louis , MO , USA
| |
Collapse
|
16
|
Novel insights into global translational regulation through Pumilio family RNA-binding protein Puf3p revealed by ribosomal profiling. Curr Genet 2018; 65:201-212. [PMID: 29951697 DOI: 10.1007/s00294-018-0862-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/16/2018] [Accepted: 06/19/2018] [Indexed: 01/13/2023]
Abstract
RNA binding proteins (RBPs) can regulate the stability, localization, and translation of their target mRNAs. Among them, Puf3p is a well-known Pumilio family RBP whose biology has been intensively studied. Nevertheless, the impact of Puf3p on the translational regulation of its downstream genes still remains to be investigated at the genome-wide level. In this study, we combined ribosome profiling and RNA-Seq in budding yeast (Saccharomyces cerevisiae) to investigate Puf3p's functions in translational regulation. Comparison of translational efficiency (TE) between wild-type and puf3Δ strains demonstrates extensive translational modulation in the absence of Puf3p (over 27% genes are affected at the genome level). Besides confirming its known role in regulating mitochondrial metabolism, our data demonstrate that Puf3p serves as a key post-transcriptional regulator of downstream RBPs by regulating their translational efficiencies, indicating a network of interactions among RBPs at the post-transcriptional level. Furthermore, Puf3p switches the balance of translational flux between mitochondrial and cytosolic ribosome biogenesis to adapt to changes in cellular metabolism. In summary, our results indicate that TE can be utilized as an informative index to interrogate the mechanism underlying RBP functions, and provide novel insights into Puf3p's mode-of-action.
Collapse
|
17
|
Liang X, Hart KJ, Dong G, Siddiqui FA, Sebastian A, Li X, Albert I, Miao J, Lindner SE, Cui L. Puf3 participates in ribosomal biogenesis in malaria parasites. J Cell Sci 2018; 131:jcs.212597. [PMID: 29487181 DOI: 10.1242/jcs.212597] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 02/16/2018] [Indexed: 12/11/2022] Open
Abstract
In this study, we characterized the Puf family gene member Puf3 in the malaria parasites Plasmodium falciparum and Plasmodium yoelii Secondary structure prediction suggested that the RNA-binding domains of the Puf3 proteins consisted of 11 pumilio repeats that were similar to those in the human Puf-A (also known as PUM3) and Saccharomyces cerevisiae Puf6 proteins, which are involved in ribosome biogenesis. Neither P. falciparum (Pf)Puf3 nor P. yoelii (Py)Puf3 could be genetically disrupted, suggesting they may be essential for the intraerythrocytic developmental cycle. Cellular fractionation of PfPuf3 in the asexual stages revealed preferential partitioning to the nuclear fraction, consistent with nuclear localization of PfPuf3::GFP and PyPuf3::GFP as detected by immunofluorescence. Furthermore, PfPuf3 colocalized with the nucleolar marker PfNop1, demonstrating that PfPuf3 is a nucleolar protein in the asexual stages. We found, however, that PyPuf3 changed its localization from being nucleolar to being present in cytosolic puncta in the mosquito and liver stages, which may reflect alternative functions in these stages. Affinity purification of molecules that associated with a PTP-tagged variant of PfPuf3 revealed 31 proteins associated with the 60S ribosome, and an enrichment of 28S rRNA and internal transcribed spacer 2 sequences. Taken together, these results suggest an essential function for PfPuf3 in ribosomal biogenesis.
Collapse
Affiliation(s)
- Xiaoying Liang
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
| | - Kevin J Hart
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
| | - Gang Dong
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, 1030 Vienna, Austria
| | - Faiza A Siddiqui
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
| | - Aswathy Sebastian
- Bioinformatics Consulting Center, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Xiaolian Li
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
| | - Istvan Albert
- Bioinformatics Consulting Center, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Jun Miao
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
| | - Scott E Lindner
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA 16802, USA
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
| |
Collapse
|
18
|
Lapointe CP, Stefely JA, Jochem A, Hutchins PD, Wilson GM, Kwiecien NW, Coon JJ, Wickens M, Pagliarini DJ. Multi-omics Reveal Specific Targets of the RNA-Binding Protein Puf3p and Its Orchestration of Mitochondrial Biogenesis. Cell Syst 2018; 6:125-135.e6. [PMID: 29248374 PMCID: PMC5799006 DOI: 10.1016/j.cels.2017.11.012] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/14/2017] [Accepted: 11/19/2017] [Indexed: 12/31/2022]
Abstract
Coenzyme Q (CoQ) is a redox-active lipid required for mitochondrial oxidative phosphorylation (OxPhos). How CoQ biosynthesis is coordinated with the biogenesis of OxPhos protein complexes is unclear. Here, we show that the Saccharomyces cerevisiae RNA-binding protein (RBP) Puf3p regulates CoQ biosynthesis. To establish the mechanism for this regulation, we employed a multi-omic strategy to identify mRNAs that not only bind Puf3p but also are regulated by Puf3p in vivo. The CoQ biosynthesis enzyme Coq5p is a critical Puf3p target: Puf3p regulates the abundance of Coq5p and prevents its detrimental hyperaccumulation, thereby enabling efficient CoQ production. More broadly, Puf3p represses a specific set of proteins involved in mitochondrial protein import, translation, and OxPhos complex assembly (pathways essential to prime mitochondrial biogenesis). Our data reveal a mechanism for post-transcriptionally coordinating CoQ production with OxPhos biogenesis, and they demonstrate the power of multi-omics for defining genuine targets of RBPs.
Collapse
Affiliation(s)
| | | | - Adam Jochem
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Paul D Hutchins
- Genome Center of Wisconsin, Madison, WI 53706, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Gary M Wilson
- Genome Center of Wisconsin, Madison, WI 53706, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Nicholas W Kwiecien
- Genome Center of Wisconsin, Madison, WI 53706, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Joshua J Coon
- Genome Center of Wisconsin, Madison, WI 53706, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Marvin Wickens
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - David J Pagliarini
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Morgridge Institute for Research, Madison, WI 53715, USA.
| |
Collapse
|
19
|
Protein-RNA networks revealed through covalent RNA marks. Nat Methods 2015; 12:1163-70. [PMID: 26524240 PMCID: PMC4707952 DOI: 10.1038/nmeth.3651] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/05/2015] [Indexed: 12/29/2022]
Abstract
Protein-RNA networks are ubiquitous and central in biological control. We present an approach, termed “RNA Tagging,” that identifies protein-RNA interactions in vivo by analyzing purified cellular RNA, without protein purification or crosslinking. An RNA-binding protein of interest is fused to an enzyme that adds uridines to the end of RNA. RNA targets bound by the chimeric protein in vivo are covalently marked with uridines and subsequently identified from extracted RNA using high-throughput sequencing. We used this approach to identify hundreds of RNAs bound by a Saccharomyces cerevisiae PUF protein, Puf3p. The method revealed that while RNA-binding proteins productively bind specific RNAs to control their function, they also “sample” RNAs without exerting a regulatory effect. We exploited the method to uncover hundreds of new and likely regulated targets for a protein without canonical RNA-binding domains, Bfr1p. The RNA Tagging approach is well-suited to detect and analyze protein-RNA networks in vivo.
Collapse
|
20
|
Integrated multi-omics analyses reveal the pleiotropic nature of the control of gene expression by Puf3p. Sci Rep 2015; 5:15518. [PMID: 26493364 PMCID: PMC4616039 DOI: 10.1038/srep15518] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/29/2015] [Indexed: 01/11/2023] Open
Abstract
The PUF family of RNA-binding proteins regulate gene expression post-transcriptionally. Saccharomyces cerevisiae Puf3p is characterised as binding nuclear-encoded mRNAs specifying mitochondrial proteins. Extensive studies of its regulation of COX17 demonstrate its role in mRNA decay. Using integrated genome-wide approaches we define an expanded set of Puf3p target mRNAs and quantitatively assessed the global impact of loss of PUF3 on gene expression using mRNA and polysome profiling and quantitative proteomics. In agreement with prior studies, our sequencing of affinity-purified Puf3-TAP associated mRNAs (RIP-seq) identified mRNAs encoding mitochondrially-targeted proteins. Additionally, we also found 720 new mRNA targets that predominantly encode proteins that enter the nucleus. Comparing transcript levels in wild-type and puf3∆ cells revealed that only a small fraction of mRNA levels alter, suggesting Puf3p determines mRNA stability for only a limited subset of its target mRNAs. Finally, proteomic and translatomic studies suggest that loss of Puf3p has widespread, but modest, impact on mRNA translation. Taken together our integrated multi-omics data point to multiple classes of Puf3p targets, which display coherent post-transcriptional regulatory properties and suggest Puf3p plays a broad, but nuanced, role in the fine-tuning of gene expression.
Collapse
|
21
|
Glucose-Regulated Phosphorylation of the PUF Protein Puf3 Regulates the Translational Fate of Its Bound mRNAs and Association with RNA Granules. Cell Rep 2015; 11:1638-50. [PMID: 26051939 DOI: 10.1016/j.celrep.2015.05.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 03/04/2015] [Accepted: 05/06/2015] [Indexed: 01/07/2023] Open
Abstract
PUF proteins are post-transcriptional regulators that bind to the 3' UTRs of mRNA transcripts. Herein, we show how a yeast PUF protein, Puf3p, responds to glucose availability to switch the fate of its bound transcripts that encode proteins required for mitochondrial biogenesis. Upon glucose depletion, Puf3p becomes heavily phosphorylated within its N-terminal region of low complexity, associates with polysomes, and promotes translation of its target mRNAs. Such nutrient-responsive phosphorylation toggles the activity of Puf3p to promote either degradation or translation of these mRNAs according to the needs of the cell. Moreover, activation of translation of pre-existing mRNAs might enable rapid adjustment to environmental changes without the need for de novo transcription. Strikingly, a Puf3p phosphomutant no longer promotes translation but becomes trapped in intracellular foci in an mRNA-dependent manner. Our findings suggest that the inability to properly resolve Puf3p-containing RNA-protein granules via a phosphorylation-based mechanism might be toxic to a cell.
Collapse
|
22
|
Shalem O, Sharon E, Lubliner S, Regev I, Lotan-Pompan M, Yakhini Z, Segal E. Systematic dissection of the sequence determinants of gene 3' end mediated expression control. PLoS Genet 2015; 11:e1005147. [PMID: 25875337 PMCID: PMC4398552 DOI: 10.1371/journal.pgen.1005147] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 03/17/2015] [Indexed: 01/09/2023] Open
Abstract
The 3'end genomic region encodes a wide range of regulatory process including mRNA stability, 3' end processing and translation. Here, we systematically investigate the sequence determinants of 3' end mediated expression control by measuring the effect of 13,000 designed 3' end sequence variants on constitutive expression levels in yeast. By including a high resolution scanning mutagenesis of more than 200 native 3' end sequences in this designed set, we found that most mutations had only a mild effect on expression, and that the vast majority (~90%) of strongly effecting mutations localized to a single positive TA-rich element, similar to a previously described 3' end processing efficiency element, and resulted in up to ten-fold decrease in expression. Measurements of 3' UTR lengths revealed that these mutations result in mRNAs with aberrantly long 3'UTRs, confirming the role for this element in 3' end processing. Interestingly, we found that other sequence elements that were previously described in the literature to be part of the polyadenylation signal had a minor effect on expression. We further characterize the sequence specificities of the TA-rich element using additional synthetic 3' end sequences and show that its activity is sensitive to single base pair mutations and strongly depends on the A/T content of the surrounding sequences. Finally, using a computational model, we show that the strength of this element in native 3' end sequences can explain some of their measured expression variability (R = 0.41). Together, our results emphasize the importance of efficient 3' end processing for endogenous protein levels and contribute to an improved understanding of the sequence elements involved in this process.
Collapse
Affiliation(s)
- Ophir Shalem
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Eilon Sharon
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Shai Lubliner
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Ifat Regev
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Maya Lotan-Pompan
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
| | - Zohar Yakhini
- Department of Computer Science, Technion, Haifa, Israel
- Agilent Laboratories, Tel Aviv, Israel
| | - Eran Segal
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
- * E-mail:
| |
Collapse
|
23
|
Russo J, Olivas WM. Conditional regulation of Puf1p, Puf4p, and Puf5p activity alters YHB1 mRNA stability for a rapid response to toxic nitric oxide stress in yeast. Mol Biol Cell 2015; 26:1015-29. [PMID: 25631823 PMCID: PMC4357503 DOI: 10.1091/mbc.e14-10-1452] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Puf RNA-binding proteins regulate mRNA stability and translation. This work elucidates the role of three yeast Puf proteins in regulating YHB1 mRNA stability in response to cell stress. Without stress, a precise balance of Puf1p, Puf4p, and Puf5p promotes decay of YHB1. Stress conditions inactivate Pufs to stabilize YHB1 and promote cell fitness. Puf proteins regulate mRNA degradation and translation through interactions with 3′ untranslated regions (UTRs). Such regulation provides an efficient method to rapidly alter protein production during cellular stress. YHB1 encodes the only protein to detoxify nitric oxide in yeast. Here we show that YHB1 mRNA is destabilized by Puf1p, Puf4p, and Puf5p through two overlapping Puf recognition elements (PREs) in the YHB1 3′ UTR. Overexpression of any of the three Pufs is sufficient to fully rescue wild-type decay in the absence of other Pufs, and overexpression of Puf4p or Puf5p can enhance the rate of wild-type decay. YHB1 mRNA decay stimulation by Puf proteins is also responsive to cellular stress. YHB1 mRNA is stabilized in galactose and high culture density, indicating inactivation of the Puf proteins. This condition-specific inactivation of Pufs is overcome by Puf overexpression, and Puf4p/Puf5p overexpression during nitric oxide exposure reduces the steady-state level of endogenous YHB1 mRNA, resulting in slow growth. Puf inactivation is not a result of altered expression or localization. Puf1p and Puf4p can bind target mRNA in inactivating conditions; however, Puf5p binding is reduced. This work demonstrates how multiple Puf proteins coordinately regulate YHB1 mRNA to protect cells from nitric oxide stress.
Collapse
Affiliation(s)
- Joseph Russo
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121-4499
| | - Wendy M Olivas
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121-4499
| |
Collapse
|
24
|
Harnessing natural sequence variation to dissect posttranscriptional regulatory networks in yeast. G3-GENES GENOMES GENETICS 2014; 4:1539-53. [PMID: 24938291 PMCID: PMC4132183 DOI: 10.1534/g3.114.012039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Understanding how genomic variation influences phenotypic variation through the molecular networks of the cell is one of the central challenges of biology. Transcriptional regulation has received much attention, but equally important is the posttranscriptional regulation of mRNA stability. Here we applied a systems genetics approach to dissect posttranscriptional regulatory networks in the budding yeast Saccharomyces cerevisiae. Quantitative sequence-to-affinity models were built from high-throughput in vivo RNA binding protein (RBP) binding data for 15 yeast RBPs. Integration of these models with genome-wide mRNA expression data allowed us to estimate protein-level RBP regulatory activity for individual segregants from a genetic cross between two yeast strains. Treating these activities as a quantitative trait, we mapped trans-acting loci (activity quantitative trait loci, or aQTLs) that act via posttranscriptional regulation of transcript stability. We predicted and experimentally confirmed that a coding polymorphism at the IRA2 locus modulates Puf4p activity. Our results also indicate that Puf3p activity is modulated by distinct loci, depending on whether it acts via the 5′ or the 3′ untranslated region of its target mRNAs. Together, our results validate a general strategy for dissecting the connectivity between posttranscriptional regulators and their upstream signaling pathways.
Collapse
|
25
|
Miller MA, Russo J, Fischer AD, Lopez Leban FA, Olivas WM. Carbon source-dependent alteration of Puf3p activity mediates rapid changes in the stabilities of mRNAs involved in mitochondrial function. Nucleic Acids Res 2013; 42:3954-70. [PMID: 24371272 PMCID: PMC3973295 DOI: 10.1093/nar/gkt1346] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The Puf family of RNA-binding proteins regulates gene expression primarily by interacting with the 3′ untranslated region (3′ UTR) of targeted mRNAs and inhibiting translation and/or stimulating decay. Physical association and computational analyses of yeast Puf3p identified >150 potential mRNA targets involved in mitochondrial function. However, only COX17 has been established as a target of Puf3p-mediated deadenylation and decapping. We have identified 10 new targets that are rapidly degraded in a Puf3p-dependent manner. We also observed changes in Puf3p activity in response to environmental conditions. Puf3p promotes rapid degradation of mRNA targets in the fermentable carbon source dextrose. However, Puf3p-mediated decay activity is inhibited in carbon sources that require mitochondrial function for efficient cell growth. In addition, the activity of Puf3p is rapidly altered by changing the carbon source. PUF3 expression is not decreased at the RNA or protein level by different carbon sources and localization is not significantly altered, suggesting that Puf3p activity is regulated posttranslationally. Finally, under conditions when Puf3p is unable to stimulate decay, Puf3p can still bind its target mRNAs. Together, these experiments provide insight into the carbon source-specific control of Puf3p activity and how such alterations allow Puf3p to dynamically regulate mitochondrial function.
Collapse
Affiliation(s)
- Melanie A Miller
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121-4499, USA
| | | | | | | | | |
Collapse
|
26
|
Rowe W, Kershaw CJ, Castelli LM, Costello JL, Ashe MP, Grant CM, Sims PFG, Pavitt GD, Hubbard SJ. Puf3p induces translational repression of genes linked to oxidative stress. Nucleic Acids Res 2013; 42:1026-41. [PMID: 24163252 PMCID: PMC3902938 DOI: 10.1093/nar/gkt948] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In response to stress, the translation of many mRNAs in yeast can change in a fashion discordant with the general repression of translation. Here, we use machine learning to mine the properties of these mRNAs to determine specific translation control signals. We find a strong association between transcripts acutely translationally repressed under oxidative stress and those associated with the RNA-binding protein Puf3p, a known regulator of cellular mRNAs encoding proteins targeted to mitochondria. Under oxidative stress, a PUF3 deleted strain exhibits more robust growth than wild-type cells and the shift in translation from polysomes to monosomes is attenuated, suggesting puf3Δ cells perceive less stress. In agreement, the ratio of reduced:oxidized glutathione, a major antioxidant and indicator of cellular redox state, is increased in unstressed puf3Δ cells but remains lower under stress. In untreated conditions, Puf3p migrates with polysomes rather than ribosome-free fractions, but this is lost under stress. Finally, reverse transcriptase-polymerase chain reaction (RT-PCR) of Puf3p targets following affinity purification shows Puf3p-mRNA associations are maintained or increased under oxidative stress. Collectively, these results point to Puf3p acting as a translational repressor in a manner exceeding the global translational response, possibly by temporarily limiting synthesis of new mitochondrial proteins as cells adapt to the stress.
Collapse
Affiliation(s)
- William Rowe
- The Faculty of Life Sciences, The Michael Smith Building, The University of Manchester, Oxford Road, Manchester M13 9PT, UK and Manchester Institute of Biotechnology (MIB), Faculty of Life Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Yamanishi M, Ito Y, Kintaka R, Imamura C, Katahira S, Ikeuchi A, Moriya H, Matsuyama T. A genome-wide activity assessment of terminator regions in Saccharomyces cerevisiae provides a ″terminatome″ toolbox. ACS Synth Biol 2013; 2:337-47. [PMID: 23654277 DOI: 10.1021/sb300116y] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The terminator regions of eukaryotes encode functional elements in the 3' untranslated region (3'-UTR) that influence the 3'-end processing of mRNA, mRNA stability, and translational efficiency, which can modulate protein production. However, the contribution of these terminator regions to gene expression remains unclear, and therefore their utilization in metabolic engineering or synthetic genetic circuits has been limited. Here, we comprehensively evaluated the activity of 5302 terminator regions from a total of 5880 genes in the budding yeast Saccharomyces cerevisiae by inserting each terminator region downstream of the P TDH3 - green fluorescent protein (GFP) reporter gene and measuring the fluorescent intensity of GFP. Terminator region activities relative to that of the PGK1 standard terminator ranged from 0.036 to 2.52, with a mean of 0.87. We thus could isolate the most and least active terminator regions. The activities of the terminator regions showed a positive correlation with mRNA abundance, indicating that the terminator region is a determinant of mRNA abundance. The least active terminator regions tended to encode longer 3'-UTRs, suggesting the existence of active degradation mechanisms for those mRNAs. The terminator regions of ribosomal protein genes tended to be the most active, suggesting the existence of a common regulator of those genes. The ″terminatome″ (the genome-wide set of terminator regions) thus not only provides valuable information to understand the modulatory roles of terminator regions on gene expression but also serves as a useful toolbox for the development of metabolically and genetically engineered yeast.
Collapse
Affiliation(s)
| | | | - Reiko Kintaka
- Research Core for Interdisciplinary
Sciences, Okayama University, 3-1-1 Tsushima-Naka,
Kita-ku, Okayama, 700-8530, Japan
| | | | | | | | - Hisao Moriya
- Research Core for Interdisciplinary
Sciences, Okayama University, 3-1-1 Tsushima-Naka,
Kita-ku, Okayama, 700-8530, Japan
| | | |
Collapse
|
28
|
Abstract
The mitochondrion is arguably the most complex organelle in the budding yeast cell cytoplasm. It is essential for viability as well as respiratory growth. Its innermost aqueous compartment, the matrix, is bounded by the highly structured inner membrane, which in turn is bounded by the intermembrane space and the outer membrane. Approximately 1000 proteins are present in these organelles, of which eight major constituents are coded and synthesized in the matrix. The import of mitochondrial proteins synthesized in the cytoplasm, and their direction to the correct soluble compartments, correct membranes, and correct membrane surfaces/topologies, involves multiple pathways and macromolecular machines. The targeting of some, but not all, cytoplasmically synthesized mitochondrial proteins begins with translation of messenger RNAs localized to the organelle. Most proteins then pass through the translocase of the outer membrane to the intermembrane space, where divergent pathways sort them to the outer membrane, inner membrane, and matrix or trap them in the intermembrane space. Roughly 25% of mitochondrial proteins participate in maintenance or expression of the organellar genome at the inner surface of the inner membrane, providing 7 membrane proteins whose synthesis nucleates the assembly of three respiratory complexes.
Collapse
|
29
|
Weis BL, Schleiff E, Zerges W. Protein targeting to subcellular organelles via MRNA localization. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:260-73. [PMID: 23457718 DOI: 10.1016/j.bbamcr.2012.04.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cells have complex membranous organelles for the compartmentalization and the regulation of most intracellular processes. Organelle biogenesis and maintenance requires newly synthesized proteins, each of which needs to go from the ribosome translating its mRNA to the correct membrane for insertion or transclocation to an a organellar subcompartment. Decades of research have revealed how proteins are targeted to the correct organelle and translocated across one or more organelle membranes ro the compartment where they function. The paradigm examples involve interactions between a peptide sequence in the protein, localization factors, and various membrane embedded translocation machineries. Membrane translocation is either cotranslational or posttranslational depending on the protein and target organelle. Meanwhile research in embryos, neurons and yeast revealed an alternative targeting mechanism in which the mRNA is localized and only then translated to synthesize the protein in the correct location. In these cases, the targeting information is coded by the cis-acting sequences in the mRNA ("Zipcodes") that interact with localization factors and, in many cases, are transported by the molecular motors on the cytoskeletal filaments. Recently, evidence has been found for this "mRNA based" mechanism in organelle protein targeting to endoplasmic reticulum, mitochondria, and the photosynthetic membranes within chloroplasts. Here we review known and potential roles of mRNA localization in protein targeting to and within organelles. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids.
Collapse
Affiliation(s)
- Benjamin L Weis
- Goether University, Cluster of Excellence Macromolecular Complexes, Institute for Molecular Biosciences, Max-von-Laue Str. 9, D-60438 Frankfort, Germany
| | | | | |
Collapse
|
30
|
Measurements of the impact of 3' end sequences on gene expression reveal wide range and sequence dependent effects. PLoS Comput Biol 2013; 9:e1002934. [PMID: 23505350 PMCID: PMC3591272 DOI: 10.1371/journal.pcbi.1002934] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 01/08/2013] [Indexed: 12/21/2022] Open
Abstract
A full understanding of gene regulation requires an understanding of the contributions that the various regulatory regions have on gene expression. Although it is well established that sequences downstream of the main promoter can affect expression, our understanding of the scale of this effect and how it is encoded in the DNA is limited. Here, to measure the effect of native S. cerevisiae 3′ end sequences on expression, we constructed a library of 85 fluorescent reporter strains that differ only in their 3′ end region. Notably, despite being driven by the same strong promoter, our library spans a continuous twelve-fold range of expression values. These measurements correlate with endogenous mRNA levels, suggesting that the 3′ end contributes to constitutive differences in mRNA levels. We used deep sequencing to map the 3′UTR ends of our strains and show that determination of polyadenylation sites is intrinsic to the local 3′ end sequence. Polyadenylation mapping was followed by sequence analysis, we found that increased A/T content upstream of the main polyadenylation site correlates with higher expression, both in the library and genome-wide, suggesting that native genes differ by the encoded efficiency of 3′ end processing. Finally, we use single cells fluorescence measurements, in different promoter activation levels, to show that 3′ end sequences modulate protein expression dynamics differently than promoters, by predominantly affecting the size of protein production bursts as opposed to the frequency at which these bursts occur. Altogether, our results lead to a more complete understanding of gene regulation by demonstrating that 3′ end regions have a unique and sequence dependent effect on gene expression. A basic question in gene expression is the relative contribution of different regulatory layers and genomic regions to the differences in protein levels. In this work we concentrated on the effect of 3′ end sequences. For this, we constructed a library of yeast strains that differ only by a native 3′ end region integrated downstream to a reported gene driven by a constant inducible promoter. Thus we could attribute all differences in reporter expression between the strains to the different 3′ end sequences. Interestingly, we found that despite being driven by the same strong, inducible promoter, our library spanned a wide and continuous range of expression levels of more than twelve-fold. As these measurements represent the sole effect of the 3′ end region, we quantify the contribution of these sequences to the variance in mRNA levels by comparing our measurements to endogenous mRNA levels. We follow by sequence analysis to find a simple sequence signature that correlates with expression. In addition, single cell analysis reveals distinct noise dynamics of 3′ end mediated differences in expression compared to different levels of promoter activation leading to a more complete understanding of gene expression which also incorporates the effect of these regions.
Collapse
|
31
|
Freeberg MA, Han T, Moresco JJ, Kong A, Yang YC, Lu ZJ, Yates JR, Kim JK. Pervasive and dynamic protein binding sites of the mRNA transcriptome in Saccharomyces cerevisiae. Genome Biol 2013; 14:R13. [PMID: 23409723 PMCID: PMC4053964 DOI: 10.1186/gb-2013-14-2-r13] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 02/14/2013] [Indexed: 01/31/2023] Open
Abstract
Background Protein-RNA interactions are integral components of nearly every aspect of biology, including regulation of gene expression, assembly of cellular architectures, and pathogenesis of human diseases. However, studies in the past few decades have only uncovered a small fraction of the vast landscape of the protein-RNA interactome in any organism, and even less is known about the dynamics of protein-RNA interactions under changing developmental and environmental conditions. Results Here, we describe the gPAR-CLIP (global photoactivatable-ribonucleoside-enhanced crosslinking and immunopurification) approach for capturing regions of the untranslated, polyadenylated transcriptome bound by RNA-binding proteins (RBPs) in budding yeast. We report over 13,000 RBP crosslinking sites in untranslated regions (UTRs) covering 72% of protein-coding transcripts encoded in the genome, confirming 3' UTRs as major sites for RBP interaction. Comparative genomic analyses reveal that RBP crosslinking sites are highly conserved, and RNA folding predictions indicate that secondary structural elements are constrained by protein binding and may serve as generalizable modes of RNA recognition. Finally, 38% of 3' UTR crosslinking sites show changes in RBP occupancy upon glucose or nitrogen deprivation, with major impacts on metabolic pathways as well as mitochondrial and ribosomal gene expression. Conclusions Our study offers an unprecedented view of the pervasiveness and dynamics of protein-RNA interactions in vivo.
Collapse
|
32
|
Van Etten J, Schagat TL, Hrit J, Weidmann CA, Brumbaugh J, Coon JJ, Goldstrohm AC. Human Pumilio proteins recruit multiple deadenylases to efficiently repress messenger RNAs. J Biol Chem 2012; 287:36370-83. [PMID: 22955276 PMCID: PMC3476303 DOI: 10.1074/jbc.m112.373522] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 09/05/2012] [Indexed: 11/06/2022] Open
Abstract
PUF proteins are a conserved family of eukaryotic RNA-binding proteins that regulate specific mRNAs: they control many processes including stem cell proliferation, fertility, and memory formation. PUFs repress protein expression from their target mRNAs but the mechanism by which they do so remains unclear, especially for humans. Humans possess two PUF proteins, PUM1 and PUM2, which exhibit similar RNA binding specificities. Here we report new insights into their regulatory activities and mechanisms of action. We developed functional assays to measure sequence-specific repression by PUM1 and PUM2. Both robustly inhibit translation and promote mRNA degradation. Purified PUM complexes were found to contain subunits of the CCR4-NOT (CNOT) complex, which contains multiple enzymes that catalyze mRNA deadenylation. PUMs interact with the CNOT deadenylase subunits in vitro. We used three approaches to determine the importance of deadenylases for PUM repression. First, dominant-negative mutants of CNOT7 and CNOT8 reduced PUM repression. Second, RNA interference depletion of the deadenylases alleviated PUM repression. Third, the poly(A) tail was necessary for maximal PUM repression. These findings demonstrate a conserved mechanism of PUF-mediated repression via direct recruitment of the CCR4-POP2-NOT deadenylase leading to translational inhibition and mRNA degradation. A second, deadenylation independent mechanism was revealed by the finding that PUMs repress an mRNA that lacks a poly(A) tail. Thus, human PUMs are repressors capable of deadenylation-dependent and -independent modes of repression.
Collapse
Affiliation(s)
- Jamie Van Etten
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600
| | - Trista L. Schagat
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600
- the Promega Corporation, Madison, Wisconsin 53711, and
| | - Joel Hrit
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600
| | - Chase A. Weidmann
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600
| | - Justin Brumbaugh
- the Departments of Chemistry and Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Joshua J. Coon
- the Departments of Chemistry and Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Aaron C. Goldstrohm
- From the Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600
| |
Collapse
|
33
|
A eukaryotic translation initiation factor 4E-binding protein promotes mRNA decapping and is required for PUF repression. Mol Cell Biol 2012; 32:4181-94. [PMID: 22890846 DOI: 10.1128/mcb.00483-12] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PUF proteins are eukaryotic RNA-binding proteins that repress specific mRNAs. The mechanisms and corepressors involved in PUF repression remain to be fully identified. Here, we investigated the mode of repression by Saccharomyces cerevisiae Puf5p and Puf4p and found that Puf5p specifically requires Eap1p to repress mRNAs, whereas Puf4p does not. Surprisingly, we observed that Eap1p, which is a member of the eukaryotic translation initiation factor 4E (eIF4E)-binding protein (4E-BP) class of translational inhibitors, does not inhibit the efficient polyribosome association of a Puf5p target mRNA. Rather, we found that Eap1p accelerates mRNA degradation by promoting decapping, and the ability of Eap1p to interact with eIF4E facilitates this activity. Deletion of EAP1 dramatically reduces decapping, resulting in accumulation of deadenylated, capped mRNA. In support of this phenotype, Eap1p associates both with Puf5p and the Dhh1p decapping factor. Furthermore, recruitment of Eap1p to downregulated mRNA is mediated by Puf5p. On the basis of these results, we propose that Puf5p promotes decapping by recruiting Eap1p and associated decapping factors to mRNAs. The implication of these findings is that a 4E-BP can repress protein expression by promoting specific mRNA degradation steps in addition to or in lieu of inhibiting translation initiation.
Collapse
|
34
|
Drosophila Pumilio protein contains multiple autonomous repression domains that regulate mRNAs independently of Nanos and brain tumor. Mol Cell Biol 2011; 32:527-40. [PMID: 22064486 DOI: 10.1128/mcb.06052-11] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Drosophila melanogaster Pumilio is an RNA-binding protein that potently represses specific mRNAs. In developing embryos, Pumilio regulates a key morphogen, Hunchback, in collaboration with the cofactor Nanos. To investigate repression by Pumilio and Nanos, we created cell-based assays and found that Pumilio inhibits translation and enhances mRNA decay independent of Nanos. Nanos robustly stimulates repression through interactions with the Pumilio RNA-binding domain. We programmed Pumilio to recognize a new binding site, which garners repression of new target mRNAs. We show that cofactors Brain Tumor and eIF4E Homologous Protein are not obligatory for Pumilio and Nanos activity. The conserved RNA-binding domain of Pumilio was thought to be sufficient for its function. Instead, we demonstrate that three unique domains in the N terminus of Pumilio possess the major repressive activity and can function autonomously. The N termini of insect and vertebrate Pumilio and Fem-3 binding factors (PUFs) are related, and we show that corresponding regions of human PUM1 and PUM2 have repressive activity. Other PUF proteins lack these repression domains. Our findings suggest that PUF proteins have evolved new regulatory functions through protein sequences appended to their conserved PUF repeat RNA-binding domains.
Collapse
|
35
|
Tanaka M, Sakai Y, Yamada O, Shintani T, Gomi K. In silico analysis of 3'-end-processing signals in Aspergillus oryzae using expressed sequence tags and genomic sequencing data. DNA Res 2011; 18:189-200. [PMID: 21586533 PMCID: PMC3111234 DOI: 10.1093/dnares/dsr011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To investigate 3'-end-processing signals in Aspergillus oryzae, we created a nucleotide sequence data set of the 3'-untranslated region (3' UTR) plus 100 nucleotides (nt) sequence downstream of the poly(A) site using A. oryzae expressed sequence tags and genomic sequencing data. This data set comprised 1065 sequences derived from 1042 unique genes. The average 3' UTR length in A. oryzae was 241 nt, which is greater than that in yeast but similar to that in plants. The 3' UTR and 100 nt sequence downstream of the poly(A) site is notably U-rich, while the region located 15-30 nt upstream of the poly(A) site is markedly A-rich. The most frequently found hexanucleotide in this A-rich region is AAUGAA, although this sequence accounts for only 6% of all transcripts. These data suggested that A. oryzae has no highly conserved sequence element equivalent to AAUAAA, a mammalian polyadenylation signal. We identified that putative 3'-end-processing signals in A. oryzae, while less well conserved than those in mammals, comprised four sequence elements: the furthest upstream U-rich element, A-rich sequence, cleavage site, and downstream U-rich element flanking the cleavage site. Although these putative 3'-end-processing signals are similar to those in yeast and plants, some notable differences exist between them.
Collapse
Affiliation(s)
- Mizuki Tanaka
- Laboratory of Bioindustrial Genomics, Department of Bioindustrial Informatics and Genomics, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
| | | | | | | | | |
Collapse
|
36
|
Quenault T, Lithgow T, Traven A. PUF proteins: repression, activation and mRNA localization. Trends Cell Biol 2011; 21:104-12. [DOI: 10.1016/j.tcb.2010.09.013] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 09/20/2010] [Accepted: 09/28/2010] [Indexed: 12/15/2022]
|
37
|
Miller MA, Olivas WM. Roles of Puf proteins in mRNA degradation and translation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 2:471-92. [PMID: 21957038 DOI: 10.1002/wrna.69] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Puf proteins are regulators of diverse eukaryotic processes including stem cell maintenance, organelle biogenesis, oogenesis, neuron function, and memory formation. At the molecular level, Puf proteins promote translational repression and/or degradation of target mRNAs by first interacting with conserved cis-elements in the 3' untranslated region (UTR). Once bound to an mRNA, Puf proteins elicit RNA repression by complex interactions with protein cofactors and regulatory machinery involved in translation and degradation. Recent work has dramatically increased our understanding of the targets of Puf protein regulation, as well as the mechanisms by which Puf proteins recognize and regulate those mRNA targets. Crystal structure analysis of several Puf-RNA complexes has demonstrated that while Puf proteins are extremely conserved in their RNA-binding domains, Pufs attain target specificity by utilizing different structural conformations to recognize 8-10 nt sequences. Puf proteins have also evolved modes of protein interactions that are organism and transcript-specific, yet two common mechanisms of repression have emerged: inhibition of cap-binding events to block translation initiation, and recruitment of the CCR4-POP2-NOT deadenylase complex for poly(A) tail removal. Finally, multiple schemes to regulate Puf protein activity have been identified, including post-translational mechanisms that allow rapid changes in the repression of mRNA targets.
Collapse
Affiliation(s)
- Melanie A Miller
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO, USA
| | | |
Collapse
|
38
|
Cridge AG, Castelli LM, Smirnova JB, Selley JN, Rowe W, Hubbard SJ, McCarthy JEG, Ashe MP, Grant CM, Pavitt GD. Identifying eIF4E-binding protein translationally-controlled transcripts reveals links to mRNAs bound by specific PUF proteins. Nucleic Acids Res 2010; 38:8039-50. [PMID: 20705650 PMCID: PMC3001062 DOI: 10.1093/nar/gkq686] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
eIF4E-binding proteins (4E-BPs) regulate translation of mRNAs in eukaryotes. However the extent to which specific mRNA targets are regulated by 4E-BPs remains unknown. We performed translational profiling by microarray analysis of polysome and monosome associated mRNAs in wild-type and mutant cells to identify mRNAs in yeast regulated by the 4E-BPs Caf20p and Eap1p; the first-global comparison of 4E-BP target mRNAs. We find that yeast 4E-BPs modulate the translation of >1000 genes. Most target mRNAs differ between the 4E-BPs revealing mRNA specificity for translational control by each 4E-BP. This is supported by observations that eap1Δ and caf20Δ cells have different nitrogen source utilization defects, implying different mRNA targets. To account for the mRNA specificity shown by each 4E-BP, we found correlations between our data sets and previously determined targets of yeast mRNA-binding proteins. We used affinity chromatography experiments to uncover specific RNA-stabilized complexes formed between Caf20p and Puf4p/Puf5p and between Eap1p and Puf1p/Puf2p. Thus the combined action of each 4E-BP with specific 3'-UTR-binding proteins mediates mRNA-specific translational control in yeast, showing that this form of translational control is more widely employed than previously thought.
Collapse
Affiliation(s)
- Andrew G Cridge
- The Michael Smith Building, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Jiang H, Guan W, Gu Z. Tinkering evolution of post-transcriptional RNA regulons: puf3p in fungi as an example. PLoS Genet 2010; 6:e1001030. [PMID: 20661438 PMCID: PMC2908677 DOI: 10.1371/journal.pgen.1001030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 06/16/2010] [Indexed: 11/19/2022] Open
Abstract
Genome-wide studies of post-transcriptional mRNA regulation in model organisms indicate a "post-transcriptional RNA regulon" model, in which a set of functionally related genes is regulated by mRNA-binding RNAs or proteins. One well-studied post-transcriptional regulon by Puf3p functions in mitochondrial biogenesis in budding yeast. The evolution of the Puf3p regulon remains unclear because previous studies have shown functional divergence of Puf3p regulon targets among yeast, fruit fly, and humans. By analyzing evolutionary patterns of Puf3p and its targeted genes in forty-two sequenced fungi, we demonstrated that, although the Puf3p regulon is conserved among all of the studied fungi, the dedicated regulation of mitochondrial biogenesis by Puf3p emerged only in the Saccharomycotina clade. Moreover, the evolution of the Puf3p regulon was coupled with evolution of codon usage bias in down-regulating expression of genes that function in mitochondria in yeast species after genome duplication. Our results provide a scenario for how evolution like a tinker exploits pre-existing materials of a conserved post-transcriptional regulon to regulate gene expression for novel functional roles.
Collapse
Affiliation(s)
- Huifeng Jiang
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, United States of America
| | - Wenjun Guan
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zhenglong Gu
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, United States of America
- * E-mail:
| |
Collapse
|
40
|
Li X, Quon G, Lipshitz HD, Morris Q. Predicting in vivo binding sites of RNA-binding proteins using mRNA secondary structure. RNA (NEW YORK, N.Y.) 2010; 16:1096-107. [PMID: 20418358 PMCID: PMC2874161 DOI: 10.1261/rna.2017210] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
While many RNA-binding proteins (RBPs) bind RNA in a sequence-specific manner, their sequence preferences alone do not distinguish known target RNAs from other potential targets that are coexpressed and contain the same sequence motifs. Recently, the mRNA targets of dozens of RNA-binding proteins have been identified, facilitating a systematic study of the features of target transcripts. Using these data, we demonstrate that calculating the predicted structural accessibility of a putative RBP binding site allows one to significantly improve the accuracy of predicting in vivo binding for the majority of sequence-specific RBPs. In our new in silico approach, accessibility is predicted based solely on the mRNA sequence without consideration of the locations of bound trans-factors; as such, our results suggest a greater than previously anticipated role for intrinsic mRNA secondary structure in determining RBP binding target preference. Target site accessibility aids in predicting target transcripts and the binding sites for RBPs with a range of RNA-binding domains and subcellular functions. Based on this work, we introduce a new motif-finding algorithm that identifies accessible sequence-specific RBP motifs from in vivo binding data.
Collapse
Affiliation(s)
- Xiao Li
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1E3, Canada
| | | | | | | |
Collapse
|
41
|
Lee D, Ohn T, Chiang YC, Quigley G, Yao G, Liu Y, Denis CL. PUF3 acceleration of deadenylation in vivo can operate independently of CCR4 activity, possibly involving effects on the PAB1-mRNP structure. J Mol Biol 2010; 399:562-75. [PMID: 20435044 DOI: 10.1016/j.jmb.2010.04.034] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 04/08/2010] [Accepted: 04/19/2010] [Indexed: 02/01/2023]
Abstract
The evolutionarily conserved PUF proteins stimulate CCR4 mRNA deadenylation through binding to 3' untranslated region sequences of specific mRNA. We have investigated the mechanisms by which PUF3 in Saccharomyces cerevisiae accelerates deadenylation of the COX17 mRNA. PUF3 was shown to affect PAN2 deadenylation of the COX17 mRNA independent of the presence of CCR4, suggesting that PUF3 acts through a general mechanism to affect deadenylation. Similarly, eIF4E, the cap-binding translation initiation factor known to control CCR4 deadenylation, was shown to affect PAN2 activity in vivo. PUF3 was found to be required for eIF4E effects on COX17 deadenylation. Both eIF4E and PUF3 effects on deadenylation were shown, in turn, to necessitate a functional poly(A)-binding protein (PAB1) in which removal of the RRM1 (RNA recognition motif 1) domain of PAB1 blocked both their effects on deadenylation. While removal of the proline-rich region (P domain) of PAB1 substantially reduces CCR4 deadenylation at non-PUF3-controlled mRNA and correspondingly blocked eIF4E effects on deadenylation, PUF3 essentially bypassed this P domain requirement. These results indicate that the PAB1-mRNP structure is critical for PUF3 action. We also found that multiple components of the CCR4-NOT deadenylase complex, but not PAN2, interacted with PUF3. PUF3 appears, therefore, both to act independently of CCR4 activity, possibly through effects on PAB1-mRNP structure, and to be capable of retaining the CCR4-NOT complex.
Collapse
Affiliation(s)
- Darren Lee
- Department of Biochemistry and Molecular Biology, Rudman Hall, University of New Hampshire, Durham, NH 03824, USA
| | | | | | | | | | | | | |
Collapse
|
42
|
A 5' cytosine binding pocket in Puf3p specifies regulation of mitochondrial mRNAs. Proc Natl Acad Sci U S A 2009; 106:20192-7. [PMID: 19918084 DOI: 10.1073/pnas.0812079106] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A single regulatory protein can control the fate of many mRNAs with related functions. The Puf3 protein of Saccharomyces cerevisiae is exemplary, as it binds and regulates more than 100 mRNAs that encode proteins with mitochondrial function. Here we elucidate the structural basis of that specificity. To do so, we explore the crystal structures of Puf3p complexes with 2 cognate RNAs. The key determinant of Puf3p specificity is an unusual interaction between a distinctive pocket of the protein with an RNA base outside the "core" PUF-binding site. That interaction dramatically affects binding affinity in vitro and is required for regulation in vivo. The Puf3p structures, combined with those of Puf4p in the same organism, illuminate the structural basis of natural PUF-RNA networks. Yeast Puf3p binds its own RNAs because they possess a -2C and is excluded from those of Puf4p which contain an additional nucleotide in the core-binding site.
Collapse
|
43
|
Structural basis for specific recognition of multiple mRNA targets by a PUF regulatory protein. Proc Natl Acad Sci U S A 2009; 106:20186-91. [PMID: 19901328 DOI: 10.1073/pnas.0812076106] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Caenorhabditis elegans fem-3 binding factor (FBF) is a founding member of the PUMILIO/FBF (PUF) family of mRNA regulatory proteins. It regulates multiple mRNAs critical for stem cell maintenance and germline development. Here, we report crystal structures of FBF in complex with 6 different 9-nt RNA sequences, including elements from 4 natural mRNAs. These structures reveal that FBF binds to conserved bases at positions 1-3 and 7-8. The key specificity determinant of FBF vs. other PUF proteins lies in positions 4-6. In FBF/RNA complexes, these bases stack directly with one another and turn away from the RNA-binding surface. A short region of FBF is sufficient to impart its unique specificity and lies directly opposite the flipped bases. We suggest that this region imposes a flattened curvature on the protein; hence, the requirement for the additional nucleotide. The principles of FBF/RNA recognition suggest a general mechanism by which PUF proteins recognize distinct families of RNAs yet exploit very nearly identical atomic contacts in doing so.
Collapse
|
44
|
Francischini CW, Quaggio RB. Molecular characterization of Arabidopsis thaliana PUF proteins - binding specificity and target candidates. FEBS J 2009; 276:5456-70. [DOI: 10.1111/j.1742-4658.2009.07230.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
45
|
Noé G, De Gaudenzi JG, Frasch AC. Functionally related transcripts have common RNA motifs for specific RNA-binding proteins in trypanosomes. BMC Mol Biol 2008; 9:107. [PMID: 19063746 PMCID: PMC2637893 DOI: 10.1186/1471-2199-9-107] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 12/08/2008] [Indexed: 02/08/2023] Open
Abstract
Background Trypanosomes mostly control gene expression by post-transcriptional events such as modulation of mRNA stability and translational efficiency. These mechanisms involve RNA-binding proteins (RBPs), which associate with transcripts to form messenger ribonucleoprotein (mRNP) complexes. Results In this study, we report the identification of mRNA targets for Trypanosoma cruzi U-rich RBP 1 (TcUBP1) and T. cruzi RBP 3 (TcRBP3), two phylogenetically conserved proteins among Kinetoplastids. Co-immunoprecipitated RBP-associated RNAs were extracted from mRNP complexes and binding of RBPs to several targets was confirmed by independent experimental assays. Analysis of target transcript sequences allowed the identification of different signature RNA motifs for each protein. Cis-elements for RBP binding have a stem-loop structure of 30–35 bases and are more frequently represented in the 3'-untranslated region (UTR) of mRNAs. Insertion of the correctly folded RNA elements to a non-specific mRNA rendered it into a target transcript, whereas substitution of the RNA elements abolished RBP interaction. In addition, RBPs competed for RNA-binding sites in accordance with the distribution of different and overlapping motifs in the 3'-UTRs of common mRNAs. Conclusion Functionally related transcripts were preferentially associated with a given RBP; TcUBP1 targets were enriched in genes encoding proteins involved in metabolism, whereas ribosomal protein-encoding transcripts were the largest group within TcRBP3 targets. Together, these results suggest coordinated control of different mRNA subsets at the post-transcriptional level by specific RBPs.
Collapse
Affiliation(s)
- Griselda Noé
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico Chascomús, UNSAM-CONICET, Av, Gral, Paz 5445, INTI, Edificio 24, 1650 San Martín, Provincia de Buenos Aires, Argentina.
| | | | | |
Collapse
|
46
|
Saint-Georges Y, Garcia M, Delaveau T, Jourdren L, Le Crom S, Lemoine S, Tanty V, Devaux F, Jacq C. Yeast mitochondrial biogenesis: a role for the PUF RNA-binding protein Puf3p in mRNA localization. PLoS One 2008; 3:e2293. [PMID: 18523582 PMCID: PMC2387061 DOI: 10.1371/journal.pone.0002293] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 04/17/2008] [Indexed: 01/01/2023] Open
Abstract
The asymmetric localization of mRNA plays an important role in coordinating posttranscriptional events in eukaryotic cells. We investigated the peripheral mitochondrial localization of nuclear-encoded mRNAs (MLR) in various conditions in which the mRNA binding protein context and the translation efficiency were altered. We identified Puf3p, a Pumilio family RNA-binding protein, as the first trans-acting factor controlling the MLR phenomenon. This allowed the characterization of two classes of genes whose mRNAs are translated to the vicinity of mitochondria. Class I mRNAs (256 genes) have a Puf3p binding motif in their 3'UTR region and many of them have their MLR properties deeply affected by PUF3 deletion. Conversely, mutations in the Puf3p binding motif alter the mitochondrial localization of BCS1 mRNA. Class II mRNAs (224 genes) have no Puf3p binding site and their asymmetric localization is not affected by the absence of PUF3. In agreement with a co-translational import process, we observed that the presence of puromycin loosens the interactions between most of the MLR-mRNAs and mitochondria. Unexpectedly, cycloheximide, supposed to solidify translational complexes, turned out to destabilize a class of mRNA-mitochondria interactions. Classes I and II mRNAs, which are therefore transported to the mitochondria through different pathways, correlated with different functional modules. Indeed, Class I genes code principally for the assembly factors of respiratory chain complexes and the mitochondrial translation machinery (ribosomes and translation regulators). Class II genes encode proteins of the respiratory chain or proteins involved in metabolic pathways. Thus, MLR, which is intimately linked to translation control, and the activity of mRNA-binding proteins like Puf3p, may provide the conditions for a fine spatiotemporal control of mitochondrial protein import and mitochondrial protein complex assembly. This work therefore provides new openings for the global study of mitochondria biogenesis.
Collapse
Affiliation(s)
- Yann Saint-Georges
- Laboratoire de Génétique Moléculaire CNRS-UMR8541, Ecole Normale Supérieure, Paris, France
| | - Mathilde Garcia
- Laboratoire de Génétique Moléculaire CNRS-UMR8541, Ecole Normale Supérieure, Paris, France
| | - Thierry Delaveau
- Laboratoire de Génétique Moléculaire CNRS-UMR8541, Ecole Normale Supérieure, Paris, France
| | - Laurent Jourdren
- Plateforme Transcriptome IFR36, Ecole Normale Supérieure, Paris, France
| | - Stephane Le Crom
- Plateforme Transcriptome IFR36, Ecole Normale Supérieure, Paris, France
| | - Sophie Lemoine
- Plateforme Transcriptome IFR36, Ecole Normale Supérieure, Paris, France
| | - Veronique Tanty
- Plateforme Transcriptome IFR36, Ecole Normale Supérieure, Paris, France
| | - Frederic Devaux
- Laboratoire de Génétique Moléculaire CNRS-UMR8541, Ecole Normale Supérieure, Paris, France
- * E-mail: (FD); (CJ)
| | - Claude Jacq
- Laboratoire de Génétique Moléculaire CNRS-UMR8541, Ecole Normale Supérieure, Paris, France
- Plateforme Transcriptome IFR36, Ecole Normale Supérieure, Paris, France
- * E-mail: (FD); (CJ)
| |
Collapse
|
47
|
Ribonomic analysis of human Pum1 reveals cis-trans conservation across species despite evolution of diverse mRNA target sets. Mol Cell Biol 2008; 28:4093-103. [PMID: 18411299 DOI: 10.1128/mcb.00155-08] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
PUF family proteins are among the best-characterized regulatory RNA-binding proteins in nonmammalian species, but relatively little is known about mRNA targets or functions of mammalian PUF proteins. In this study, we used ribonomic analysis to identify and analyze mRNAs associated with ribonucleoproteins containing an endogenous human PUF protein, Pum1. Pum1-associated mRNAs were highly enriched for genes encoding proteins that function in transcriptional regulation and cell cycle/proliferation, results consistent with the posttranscriptional RNA regulon model and the proposed ancestral functions of PUF proteins in stem cell biology. Analysis of 3' untranslated region sequences of Pum1-associated mRNAs revealed a core Pum1 consensus sequence, UGUAHAUA. Pum1 knockdown demonstrated that Pum1 enhances decay of associated mRNAs, and relocalization of Pum1 to stress granules suggested that Pum1 functions in repression of translation. This study is the first in vivo genome-wide mRNA target identification of a mammalian PUF protein and provides direct evidence that human PUF proteins regulate stability of associated mRNAs. Comparison of Pum1-associated mRNAs to mRNA targets of PUF proteins from Saccharomyces cerevisiae and Drosophila melanogaster demonstrates how a well-conserved RNA-binding domain and cognate binding sequence have been evolutionarily rewired to regulate the collective expression of different sets of functionally related genes.
Collapse
|
48
|
Miller MT, Higgin JJ, Hall TMT. Basis of altered RNA-binding specificity by PUF proteins revealed by crystal structures of yeast Puf4p. Nat Struct Mol Biol 2008; 15:397-402. [PMID: 18327269 DOI: 10.1038/nsmb.1390] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 01/15/2008] [Indexed: 01/26/2023]
Abstract
Pumilio/FBF (PUF) family proteins are found in eukaryotic organisms and regulate gene expression post-transcriptionally by binding to sequences in the 3' untranslated region of target transcripts. PUF proteins contain an RNA binding domain that typically comprises eight alpha-helical repeats, each of which recognizes one RNA base. Some PUF proteins, including yeast Puf4p, have altered RNA binding specificity and use their eight repeats to bind to RNA sequences with nine or ten bases. Here we report the crystal structures of Puf4p alone and in complex with a 9-nucleotide (nt) target RNA sequence, revealing that Puf4p accommodates an 'extra' nucleotide by modest adaptations allowing one base to be turned away from the RNA binding surface. Using structural information and sequence comparisons, we created a mutant Puf4p protein that preferentially binds to an 8-nt target RNA sequence over a 9-nt sequence and restores binding of each protein repeat to one RNA base.
Collapse
Affiliation(s)
- Matthew T Miller
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Building 101, Room F363, Research Triangle Park, North Carolina 27709, USA
| | | | | |
Collapse
|
49
|
Gupta YK, Nair DT, Wharton RP, Aggarwal AK. Structures of human Pumilio with noncognate RNAs reveal molecular mechanisms for binding promiscuity. Structure 2008; 16:549-57. [PMID: 18328718 DOI: 10.1016/j.str.2008.01.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 12/29/2007] [Accepted: 01/02/2008] [Indexed: 10/22/2022]
Abstract
Pumilio is a founder member of the evolutionarily conserved Puf family of RNA-binding proteins that control a number of physiological processes in eukaryotes. A structure of human Pumilio (hPum) Puf domain bound to a Drosophila regulatory sequence showed that each Puf repeat recognizes a single nucleotide. Puf domains in general bind promiscuously to a large set of degenerate sequences, but the structural basis for this promiscuity has been unclear. Here, we describe the structures of hPum Puf domain complexed to two noncognate RNAs, CycB(reverse) and Puf5. In each complex, one of the nucleotides is ejected from the binding surface, in effect, acting as a "spacer." The complexes also reveal the plasticity of several Puf repeats, which recognize noncanonical nucleotides. Together, these complexes provide a molecular basis for recognition of degenerate binding sites, which significantly increases the number of mRNAs targeted for regulation by Puf proteins in vivo.
Collapse
Affiliation(s)
- Yogesh K Gupta
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, Box 1677, 1425 Madison Avenue, New York, NY 10029, USA
| | | | | | | |
Collapse
|
50
|
Ulbricht RJ, Olivas WM. Puf1p acts in combination with other yeast Puf proteins to control mRNA stability. RNA (NEW YORK, N.Y.) 2008; 14:246-62. [PMID: 18094119 PMCID: PMC2212245 DOI: 10.1261/rna.847408] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The eukaryotic Puf proteins bind 3' untranslated region (UTR) sequence elements to regulate the stability and translation of their target transcripts, and such regulatory events are critical for cell growth and development. Several global genome analyses have identified hundreds of potential mRNA targets of the Saccharomyces cerevisiae Puf proteins; however, only three mRNA targets for these proteins have been characterized thus far. After direct testing of nearly 40 candidate mRNAs, we established two of these as true mRNA targets of Puf-mediated decay in yeast, HXK1 and TIF1. In a novel finding, multiple Puf proteins, including Puf1p, regulate both of these mRNAs in combination. TIF1 mRNA decay can be stimulated individually by Puf1p and Puf5p, but the combination of both proteins is required for full regulation. This Puf-mediated decay requires the presence of two UGUA binding sites within the TIF1 3' UTR, with one site regulated by Puf5p and the other by both Puf1p and Puf5p. Alteration of the UGUA site in the tif1 3' UTR to more closely resemble the Puf3p binding site broadens the specificity to include regulation by Puf3p. The stability of the endogenously transcribed HXK1 mRNA, cellular levels of Hxk1 protein activity, and HXK1 3' UTR-directed decay are affected by Puf1p and Puf5p as well as Puf4p. Together these results identify the first mRNA targets of Puf1p-mediated decay, describe similar yet distinct combinatorial control of two new target mRNAs by the yeast Puf proteins, and suggest the importance of direct testing to evaluate RNA-regulatory mechanisms.
Collapse
Affiliation(s)
- Randi J Ulbricht
- Department of Biology, University of Missouri-St. Louis, St. Louis, Missouri 63121, USA
| | | |
Collapse
|